From dcb6d84266a0b291781855cf623aa4d4c395f14d Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 12 Jul 2013 12:00:18 +0200
Subject: Add support for object sections

Sections are an optimization mechanism that allows the partitioning of
data members of a persistent class into groups that can be separately
loaded and/or updated.
---
 common/makefile                        |    2 +
 common/section/basics/driver.cxx       | 1689 ++++++++++++++++++++++++++++++
 common/section/basics/makefile         |  115 +++
 common/section/basics/test.hxx         |  600 +++++++++++
 common/section/basics/test.std         |    0
 common/section/polymorphism/driver.cxx | 1763 ++++++++++++++++++++++++++++++++
 common/section/polymorphism/makefile   |  115 +++
 common/section/polymorphism/test.hxx   |  495 +++++++++
 common/section/polymorphism/test.std   |    0
 9 files changed, 4779 insertions(+)
 create mode 100644 common/section/basics/driver.cxx
 create mode 100644 common/section/basics/makefile
 create mode 100644 common/section/basics/test.hxx
 create mode 100644 common/section/basics/test.std
 create mode 100644 common/section/polymorphism/driver.cxx
 create mode 100644 common/section/polymorphism/makefile
 create mode 100644 common/section/polymorphism/test.hxx
 create mode 100644 common/section/polymorphism/test.std

(limited to 'common')

diff --git a/common/makefile b/common/makefile
index 82743a1..3263410 100644
--- a/common/makefile
+++ b/common/makefile
@@ -43,6 +43,8 @@ relationship-query        \
 schema/namespace          \
 schema/embedded/basics    \
 schema/embedded/order     \
+section/basics            \
+section/polymorphism      \
 session/cache             \
 template                  \
 transaction/basics        \
diff --git a/common/section/basics/driver.cxx b/common/section/basics/driver.cxx
new file mode 100644
index 0000000..67e09ef
--- /dev/null
+++ b/common/section/basics/driver.cxx
@@ -0,0 +1,1689 @@
+// file      : common/section/basics/driver.cxx
+// copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+// Test object section basics.
+//
+
+#include <memory>   // std::auto_ptr
+#include <cassert>
+#include <iostream>
+
+#include <odb/session.hxx>
+#include <odb/database.hxx>
+#include <odb/transaction.hxx>
+
+#include <common/common.hxx>
+
+#include "test.hxx"
+#include "test-odb.hxx"
+
+using namespace std;
+using namespace odb::core;
+
+struct failed {};
+
+int
+main (int argc, char* argv[])
+{
+  try
+  {
+    auto_ptr<database> db (create_database (argc, argv));
+
+    // Test lazy-loaded, always updating section.
+    //
+    {
+      using namespace test1;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+
+      // We can also update just the section.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n != o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+
+      // Test updating unloaded section.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+      o.s.unload ();
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+        t.commit ();
+      }
+
+      // Test reloading of loaded/unloaded sections.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+      o.s.unload ();
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        db->reload (o);
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+        db->load (o, o.s);
+        t.commit ();
+      }
+
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        db->reload (o);
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+
+      typedef odb::query<object> query;
+      typedef odb::result<object> result;
+
+      // Make sure we can access section members in queries.
+      //
+      {
+        transaction t (db->begin ());
+
+        result r (db->query<object> (query::ss == o.ss));
+        result::iterator i (r.begin ());
+
+        assert (i != r.end () && !i->s.loaded ());
+
+        db->load (*i, i->s);
+        assert (i->n == o.n &&
+                i->sn == o.sn && i->ss == o.ss && i->sv == o.sv);
+
+        assert (++i == r.end ());
+
+        t.commit ();
+      }
+
+      // Make sure we can load/update sections without messing up the
+      // loaded object's image.
+      //
+      {
+        transaction t (db->begin ());
+
+        result r (db->query<object> (query::ss == o.ss));
+        result::iterator i (r.begin ());
+
+        assert (i != r.end ());
+
+        object o1;
+        i.load (o1);
+        db->load (o1, o1.s);
+        assert (o1.n == o.n &&
+                o1.sn == o.sn && o1.ss == o.ss && o1.sv == o.sv);
+
+        o.sn++;
+        o.ss += 'd';
+        o.sv[0]++;
+        db->update (o, o.s);
+
+        object o2;
+        i.load (o2);
+        db->load (o2, o2.s);
+        assert (o2.n == o1.n &&
+                o2.sn == o.sn && o2.ss == o.ss && o2.sv == o.sv);
+
+        assert (++i == r.end ());
+
+        t.commit ();
+      }
+    }
+
+    // Test lazy-loaded, change-updated section.
+    //
+    {
+      using namespace test2;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update but don't mark as changed.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+        t.commit ();
+      }
+
+      // Mark as changed.
+      //
+      o.s.change ();
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        assert (!o.s.changed ());
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+
+      // We can also update just the section manually.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+      o.s.change ();
+
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s);
+        assert (!o.s.changed ());
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n != o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+    }
+
+    // Test lazy-loaded, manually-updated section.
+    //
+    {
+      using namespace test3;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update the object only.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+        t.commit ();
+      }
+
+      // Update both the object and section.
+      //
+      o.n++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        db->update (o, o.s);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+
+      // We can also update just the section.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n != o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+
+      // Test detection of unloaded section update.
+      //
+      try
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->update (*p, p->s);
+        assert (false);
+      }
+      catch (const section_not_loaded&)
+      {
+      }
+    }
+
+    // Test eager-loaded, change-updated section.
+    //
+    {
+      using namespace test4;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update but don't mark as changed.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+        t.commit ();
+      }
+
+      // Mark as changed.
+      //
+      o.s.change ();
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        assert (!o.s.changed ());
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+    }
+
+    // Test eager-loaded, manually-updated section.
+    //
+    {
+      using namespace test5;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update the object only.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+        t.commit ();
+      }
+
+      // Update both the object and section.
+      //
+      o.n++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        db->update (o, o.s);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+
+      // We can also update just the section.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        assert (p->n != o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+    }
+
+    // Test value-only and container-only section. Also multiple sections
+    // in an object.
+    //
+    {
+      using namespace test6;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s1.loaded ());
+        assert (o.s2.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s1.loaded ());
+        assert (!p->s2.loaded ());
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+
+        db->load (*p, p->s1);
+        assert (p->s1.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv != o.sv);
+
+        db->load (*p, p->s2);
+        assert (p->s2.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s1);
+        db->load (*p, p->s2);
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+
+      // We can also update just the section.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s1);
+        db->update (o, o.s2);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s1);
+        db->load (*p, p->s2);
+        assert (p->n != o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+        t.commit ();
+      }
+    }
+
+    // Test value-only and container-only section. Also multiple sections
+    // in an object.
+    //
+    {
+      using namespace test7;
+
+      object o (123, "abc", true);
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s1.loaded ());
+        assert (o.s2.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s1.loaded ());
+        assert (!p->s2.loaded ());
+        assert (p->sn1 != o.sn1 && p->ss1 != o.ss1 &&
+                p->sn2 != o.sn2 && p->ss2 != o.ss2 && p->sb2 != o.sb2);
+
+        db->load (*p, p->s1);
+        db->load (*p, p->s2);
+        assert (p->s1.loaded ());
+        assert (p->s2.loaded ());
+        assert (p->sn1 == o.sn1 && p->ss1 == o.ss1 &&
+                p->sn2 == o.sn2 && p->ss2 == o.ss2 && p->sb2 == o.sb2);
+
+
+        t.commit ();
+      }
+
+      // Update.
+      //
+      o.sn1++;
+      o.sn2++;
+      o.ss1 += 'd';
+      o.ss2 += 'd';
+      o.sb2 = !o.sb2;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s1);
+        db->load (*p, p->s2);
+        assert (p->sn1 == o.sn1 && p->ss1 == o.ss1 &&
+                p->sn2 == o.sn2 && p->ss2 == o.ss2 && p->sb2 == o.sb2);
+        t.commit ();
+      }
+
+      // Manual update of just the section.
+      //
+      o.sn1++;
+      o.sn2++;
+      o.ss1 += 'd';
+      o.ss2 += 'd';
+      o.sb2 = !o.sb2;
+
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s2);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s1);
+        db->load (*p, p->s2);
+        assert (p->sn1 != o.sn1 && p->ss1 != o.ss1 &&
+                p->sn2 == o.sn2 && p->ss2 == o.ss2 && p->sb2 == o.sb2);
+        t.commit ();
+      }
+    }
+
+    // Test readonly and inverse section members.
+    //
+    {
+      using namespace test8;
+
+      object1 o1 (new object (123, "abc"));
+      object& o (*o1.p);
+      o.sp = &o1;
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        db->persist (o1);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        session s;
+
+        transaction t (db->begin ());
+        auto_ptr<object1> p1 (db->load<object1> (o1.id));
+        object* p (p1->p);
+
+        assert (!p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sp == 0);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sp->id == o.sp->id);
+
+        t.commit ();
+      }
+
+      // Update.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        session s;
+
+        transaction t (db->begin ());
+        auto_ptr<object1> p1 (db->load<object1> (o1.id));
+        object* p (p1->p);
+
+        db->load (*p, p->s);
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss == o.ss && p->sp->id == o.sp->id);
+
+        t.commit ();
+      }
+    }
+
+    // Test object without any columns to load or update.
+    //
+    {
+      using namespace test9;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (o.id == o.id &&
+                p->sn != o.sn && p->ss != o.ss);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (o.id == o.id &&
+                p->sn == o.sn && p->ss == o.ss);
+
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      o.sn++;
+      o.ss += 'd';
+
+      {
+        transaction t (db->begin ());
+        db->update (o); // No-op.
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (o.id == o.id &&
+                p->sn != o.sn && p->ss != o.ss);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (o.id == o.id &&
+                p->sn == o.sn && p->ss == o.ss);
+        t.commit ();
+      }
+    }
+
+    // Test section without any columns or containers to update.
+    //
+    {
+      using namespace test10;
+
+      object o (123);
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->n == o.n && p->sn != o.sn);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n && p->sn == o.sn);
+
+        t.commit ();
+      }
+
+      // Update.
+      //
+      o.n++;
+      o.sn++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        //db->update (o, o.s); // Error.
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n && p->sn != o.sn);
+        t.commit ();
+      }
+    }
+
+    // Test section with composite member.
+    //
+    {
+      using namespace test11;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->sc.s != o.sc.s && p->sc.v != o.sc.v);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->sc.s == o.sc.s && p->sc.v == o.sc.v);
+
+        t.commit ();
+      }
+
+      // Update.
+      //
+      o.n++;
+      o.sn++;
+      o.sc.s += 'd';
+      o.sc.v[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->sc.s == o.sc.s && p->sc.v == o.sc.v);
+        t.commit ();
+      }
+    }
+
+    // Test change state restoration on transaction rollback.
+    //
+    {
+      using namespace test12;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      // Update.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+      o.s.change ();
+
+      try
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        assert (!o.s.changed ());
+        throw failed ();
+      }
+      catch (const failed&)
+      {
+        assert (o.s.changed ());
+      }
+
+      // Retry. Also test the object destruction before transaction
+      // termination case.
+      //
+      {
+        transaction t (db->begin ());
+        {
+          object c (o);
+          db->update (c);
+          assert (!c.s.changed ());
+        }
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n && p->sn == o.sn && p->ss == o.ss);
+        t.commit ();
+      }
+    }
+
+    // Test section accessor/modifier.
+    //
+    {
+      using namespace test13;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s ().loaded ());
+      }
+
+      // Load.
+      //
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s ().loaded ());
+        assert (p->n == o.n && p->sn != o.sn && p->ss != o.ss);
+
+        db->load (*p, p->rw_s ());
+
+        assert (p->s ().loaded ());
+        assert (p->n == o.n && p->sn == o.sn && p->ss == o.ss);
+
+        t.commit ();
+      }
+
+      // Update.
+      //
+      o.n++;
+      o.sn++;
+      o.ss += 'd';
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        db->update (o, o.s ());
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->rw_s ());
+        assert (p->n == o.n && p->sn == o.sn && p->ss == o.ss);
+        t.commit ();
+      }
+
+      // Test detection of section copy.
+      //
+      try
+      {
+        transaction t (db->begin ());
+        section c (o.s ());
+        db->update (o, c);
+        assert (false);
+      }
+      catch (const section_not_in_object&)
+      {
+      }
+    }
+
+    // Test LOB in section streaming, column re-ordering.
+    //
+    {
+      using namespace test14;
+
+      object o (123, "\x01\x02\x03\x04\x05");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->n == o.n && p->sn != o.sn && p->sb != o.sb);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n && p->sn == o.sn && p->sb == o.sb);
+
+        t.commit ();
+      }
+
+      // Update.
+      //
+      o.n++;
+      o.sn++;
+      o.sb.push_back ('\x06');
+
+      {
+        transaction t (db->begin ());
+        db->update (o);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n == o.n && p->sn == o.sn && p->sb == o.sb);
+        t.commit ();
+      }
+
+      // We can also update just the section.
+      //
+      o.n++;
+      o.sn++;
+      o.sb.push_back ('\x07');
+
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->n != o.n && p->sn == o.sn && p->sb == o.sb);
+        t.commit ();
+      }
+    }
+
+    // Test sections and optimistic concurrency.
+    //
+    {
+      using namespace test15;
+
+      object o (123, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn != o.sn && p->ss != o.ss && p->sv != o.sv);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->n == o.n &&
+                p->sn == o.sn && p->ss == o.ss && p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      object o1 (o);
+      o1.n++;
+      o1.sn++;
+      o1.ss += 'd';
+      o1.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        db->update (o1);
+        assert (o.v != o1.v);
+
+        try
+        {
+          db->load (*p, p->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*p);
+          assert (!p->s.loaded ());
+          db->load (*p, p->s);
+
+          assert (p->n == o1.n &&
+                  p->sn == o1.sn && p->ss == o1.ss && p->sv == o1.sv);
+        }
+
+        db->reload (o);
+        assert (o.v == o1.v);
+        assert (o.n == o1.n &&
+                o.sn == o1.sn && o.ss == o1.ss && o.sv == o1.sv);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      o1.sn++;
+      o1.ss += 'd';
+      o1.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        db->update (o1, o1.s);
+        assert (o.v != o1.v);
+
+        try
+        {
+          db->load (*p, p->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*p);
+          assert (!p->s.loaded ());
+          db->load (*p, p->s);
+
+          assert (p->n == o1.n &&
+                  p->sn == o1.sn && p->ss == o1.ss && p->sv == o1.sv);
+        }
+
+        db->reload (o);
+        assert (o.v == o1.v);
+        assert (o.n == o1.n &&
+                o.sn == o1.sn && o.ss == o1.ss && o.sv == o1.sv);
+        t.commit ();
+      }
+
+      // Update changed section.
+      //
+      o1.sn++;
+      o1.ss += 'd';
+      o1.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o1, o1.s);
+
+        try
+        {
+          db->update (o, o.s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (o);
+          db->update (o, o.s);
+        }
+
+        t.commit ();
+      }
+    }
+
+    // Test container-only sections and optimistic concurrency.
+    //
+    {
+      using namespace test16;
+
+      object o (123);
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->sv != o.sv);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      object o1 (o);
+      o1.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        db->update (o1);
+        assert (o.v != o1.v);
+
+        try
+        {
+          db->load (*p, p->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*p);
+          assert (!p->s.loaded ());
+          db->load (*p, p->s);
+
+          assert (p->sv == o1.sv);
+        }
+
+        db->reload (o);
+        assert (o.v == o1.v);
+        assert (o.sv == o1.sv);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      o1.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        db->update (o1, o1.s);
+        assert (o.v != o1.v);
+
+        try
+        {
+          db->load (*p, p->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*p);
+          assert (!p->s.loaded ());
+          db->load (*p, p->s);
+
+          assert (p->sv == o1.sv);
+        }
+
+        db->reload (o);
+        assert (o.v == o1.v);
+        assert (o.sv == o1.sv);
+        t.commit ();
+      }
+
+      // Update changed section.
+      //
+      o1.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o1, o1.s);
+
+        try
+        {
+          db->update (o, o.s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (o);
+          db->update (o, o.s);
+        }
+
+        t.commit ();
+      }
+    }
+
+    // Test reuse-inheritance, sections, and optimistic concurrency.
+    //
+    {
+      using namespace test17;
+
+      object o (123);
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s1.loaded ());
+        assert (o.s2.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s1.loaded ());
+        assert (!p->s2.loaded ());
+        assert (p->s1n != o.s1n && p->s2v != o.s2v);
+
+        db->load (*p, p->s1);
+        db->load (*p, p->s2);
+
+        assert (p->s1.loaded ());
+        assert (p->s2.loaded ());
+        assert (p->s1n == o.s1n && p->s2v == o.s2v);
+
+        t.commit ();
+      }
+
+      object o1 (o);
+
+      // Update object.
+      //
+      for (unsigned short s (1); s < 3; ++s)
+      {
+        o1.s1n++;
+        o1.s2v[0]++;
+
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        db->update (o1);
+        assert (o.v != o1.v);
+
+        try
+        {
+          switch (s)
+          {
+          case 1: db->load (*p, p->s1); break;
+          case 2: db->load (*p, p->s2); break;
+          default: break;
+          }
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*p);
+
+          assert (!p->s1.loaded ());
+          assert (!p->s2.loaded ());
+
+          db->load (*p, p->s1);
+          db->load (*p, p->s2);
+
+          assert (p->s1n == o1.s1n && p->s2v == o1.s2v);
+        }
+
+        db->reload (o);
+        assert (o.v == o1.v);
+        assert (o.s1n == o1.s1n && o.s2v == o1.s2v);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      for (unsigned short s (1); s < 3; ++s)
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        switch (s)
+        {
+        case 1:
+          o1.s1n++;
+          db->update (o1, o1.s1);
+          assert (o.v != o1.v);
+          break;
+        case 2:
+          o1.s2v[0]++;
+          db->update (o1, o1.s2);
+          assert (o.v != o1.v);
+          break;
+        default: break;
+        }
+
+        try
+        {
+          switch (s)
+          {
+          case 1: db->load (*p, p->s1); break;
+          case 2: db->load (*p, p->s2); break;
+          default: break;
+          }
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*p);
+
+          assert (!p->s1.loaded ());
+          assert (!p->s2.loaded ());
+
+          db->load (*p, p->s1);
+          db->load (*p, p->s2);
+
+          assert (p->s1n == o1.s1n && p->s2v == o1.s2v);
+        }
+
+        db->reload (o);
+        assert (o.v == o1.v);
+        assert (o.s1n == o1.s1n && o.s2v == o1.s2v);
+        t.commit ();
+      }
+
+      // Update changed section.
+      //
+      for (unsigned short s (1); s < 3; ++s)
+      {
+        transaction t (db->begin ());
+
+        switch (s)
+        {
+        case 1:
+          o1.s1n++;
+          db->update (o1, o1.s1);
+          break;
+        case 2:
+          o1.s2v[0]++;
+          db->update (o1, o1.s2);
+          break;
+        default: break;
+        }
+
+        try
+        {
+          switch (s)
+          {
+          case 1: db->update (o, o.s1); break;
+          case 2: db->update (o, o.s2); break;
+          default: break;
+          }
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (o);
+
+          switch (s)
+          {
+          case 1: db->update (o, o.s1); break;
+          case 2: db->update (o, o.s2); break;
+          default: break;
+          }
+        }
+
+        db->reload (o1);
+
+        t.commit ();
+      }
+    }
+
+    // Test change-updated section and change-tracking container.
+    //
+    {
+      using namespace test18;
+
+      object o (123);
+
+      {
+        transaction t (db->begin ());
+        db->persist (o);
+        t.commit ();
+
+        assert (o.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+
+        assert (!p->s.loaded ());
+        assert (p->sn != o.sn && p->sv != o.sv);
+
+        db->load (*p, p->s);
+
+        assert (p->s.loaded ());
+        assert (p->sn == o.sn && p->sv == o.sv);
+
+        t.commit ();
+      }
+
+      // Update but don't mark as changed.
+      //
+      o.sn++;
+      o.sv.modify (0)++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o); // Automatically marked as changed.
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->sn == o.sn && p->sv == o.sv);
+        t.commit ();
+      }
+
+      // Test updating just the section manually.
+      //
+      o.sn++;
+      o.sv.modify (0)++;
+
+      {
+        transaction t (db->begin ());
+        db->update (o, o.s);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<object> p (db->load<object> (o.id));
+        db->load (*p, p->s);
+        assert (p->sn == o.sn && p->sv == o.sv);
+        t.commit ();
+      }
+    }
+  }
+  catch (const odb::exception& e)
+  {
+    cerr << e.what () << endl;
+    return 1;
+  }
+}
diff --git a/common/section/basics/makefile b/common/section/basics/makefile
new file mode 100644
index 0000000..f0484e8
--- /dev/null
+++ b/common/section/basics/makefile
@@ -0,0 +1,115 @@
+# file      : common/section/basics/makefile
+# copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC
+# license   : GNU GPL v2; see accompanying LICENSE file
+
+include $(dir $(lastword $(MAKEFILE_LIST)))../../../build/bootstrap.make
+
+cxx_tun := driver.cxx
+odb_hdr := test.hxx
+genf    := $(call odb-gen,$(odb_hdr))
+gen     := $(addprefix $(out_base)/,$(genf))
+cxx_obj := $(addprefix $(out_base)/,$(cxx_tun:.cxx=.o)) $(filter %.o,$(gen:.cxx=.o))
+cxx_od  := $(cxx_obj:.o=.o.d)
+
+common.l             := $(out_root)/libcommon/common/common.l
+common.l.cpp-options := $(out_root)/libcommon/common/common.l.cpp-options
+
+# Import.
+#
+$(call import,\
+  $(scf_root)/import/odb/stub.make,\
+  odb: odb,odb-rules: odb_rules)
+
+# Build.
+#
+$(driver): $(cxx_obj) $(common.l)
+$(cxx_obj) $(cxx_od): cpp_options := -I$(out_base) -I$(src_base)
+$(cxx_obj) $(cxx_od): $(common.l.cpp-options)
+
+$(gen): $(odb)
+$(gen): odb := $(odb)
+$(gen) $(dist): export odb_options += --generate-schema --generate-query \
+--table-prefix t_section_b_
+$(gen): cpp_options := -I$(src_base)
+$(gen): $(common.l.cpp-options)
+
+ifneq ($(db_id),common)
+$(gen): odb_options += --database $(db_id)
+else
+$(gen): odb_options += --multi-database dynamic
+endif
+
+$(call include-dep,$(cxx_od),$(cxx_obj),$(gen))
+
+# Alias for default target.
+#
+$(out_base)/: $(driver)
+
+# Dist
+#
+name := $(subst /,-,$(subst $(src_root)/common/,,$(src_base)))
+
+$(dist): sources := $(cxx_tun)
+$(dist): headers := $(odb_hdr)
+$(dist): data_dist := test.std
+$(dist): export name := $(name)
+$(dist): export extra_dist := $(data_dist) $(call vc8projs,$(name)) \
+$(call vc9projs,$(name)) $(call vc10projs,$(name)) $(call vc11projs,$(name))
+$(dist):
+	$(call dist-data,$(sources) $(headers) $(data_dist))
+	$(call meta-automake,../../template/Makefile.am)
+	$(call meta-vc8projs,../../template/template,$(name))
+	$(call meta-vc9projs,../../template/template,$(name))
+	$(call meta-vc10projs,../../template/template,$(name))
+	$(call meta-vc11projs,../../template/template,$(name))
+
+# Test.
+#
+ifneq ($(db_id),common)
+$(eval $(call test-rule))
+else
+$(foreach d,$(databases),$(eval $(call test-rule,$d)))
+endif
+
+# Clean.
+#
+$(clean):                            \
+  $(driver).o.clean                  \
+  $(addsuffix .cxx.clean,$(cxx_obj)) \
+  $(addsuffix .cxx.clean,$(cxx_od))  \
+  $(addsuffix .hxx.clean,$(filter %.cxx,$(gen)))
+	$(call message,,rm -f $(out_base)/test.out)
+
+# Generated .gitignore.
+#
+ifeq ($(out_base),$(src_base))
+$(driver): | $(out_base)/.gitignore
+
+$(out_base)/.gitignore: files := driver $(genf)
+$(clean): $(out_base)/.gitignore.clean
+
+$(call include,$(bld_root)/git/gitignore.make)
+endif
+
+# How to.
+#
+$(call include,$(bld_root)/dist.make)
+$(call include,$(bld_root)/meta/vc8proj.make)
+$(call include,$(bld_root)/meta/vc9proj.make)
+$(call include,$(bld_root)/meta/vc10proj.make)
+$(call include,$(bld_root)/meta/vc11proj.make)
+$(call include,$(bld_root)/meta/automake.make)
+
+$(call include,$(bld_root)/cxx/standard.make) # cxx_standard
+ifdef cxx_standard
+$(gen): odb_options += --std $(cxx_standard)
+$(call include,$(odb_rules))
+endif
+
+$(call include,$(bld_root)/cxx/cxx-d.make)
+$(call include,$(bld_root)/cxx/cxx-o.make)
+$(call include,$(bld_root)/cxx/o-e.make)
+
+# Dependencies.
+#
+$(call import,$(src_root)/libcommon/makefile)
diff --git a/common/section/basics/test.hxx b/common/section/basics/test.hxx
new file mode 100644
index 0000000..c129f3e
--- /dev/null
+++ b/common/section/basics/test.hxx
@@ -0,0 +1,600 @@
+// file      : common/section/basics/test.hxx
+// copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef TEST_HXX
+#define TEST_HXX
+
+#include <string>
+#include <vector>
+
+#include <odb/core.hxx>
+#include <odb/section.hxx>
+#include <odb/vector.hxx>
+
+#ifdef ODB_COMPILER
+#  if defined(ODB_DATABASE_PGSQL)
+#    define BLOB_TYPE "BYTEA"
+#  elif defined(ODB_DATABASE_MSSQL)
+#    define BLOB_TYPE "VARBINARY(max)"
+#  else
+#    define BLOB_TYPE "BLOB"
+#  endif
+#endif
+
+// Test lazy-loaded, always-updated section.
+//
+#pragma db namespace table("t1_")
+namespace test1
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : sn (n_), n (n_), ss (s_) {sv.push_back (n_);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+
+    int n;
+
+    #pragma db section(s)
+    std::string ss;
+
+    #pragma db section(s)
+    std::vector<int> sv;
+  };
+}
+
+// Test lazy-loaded, change-updated section.
+//
+#pragma db namespace table("t2_")
+namespace test2
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : sn (n_), n (n_), ss (s_) {sv.push_back (n_);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy) update(change)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+
+    int n;
+
+    #pragma db section(s)
+    std::string ss;
+
+    #pragma db section(s)
+    std::vector<int> sv;
+  };
+}
+
+// Test lazy-loaded, manually-updated section.
+//
+#pragma db namespace table("t3_")
+namespace test3
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : sn (n_), n (n_), ss (s_) {sv.push_back (n_);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy) update(manual)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+
+    int n;
+
+    #pragma db section(s)
+    std::string ss;
+
+    #pragma db section(s)
+    std::vector<int> sv;
+  };
+}
+
+// Test eager-loaded, change-updated section.
+//
+#pragma db namespace table("t4_")
+namespace test4
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : sn (n_), n (n_), ss (s_) {sv.push_back (n_);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db section(s)
+    int sn;
+
+    #pragma db update(change)
+    odb::section s;
+
+    int n;
+
+    #pragma db section(s)
+    std::string ss;
+
+    #pragma db section(s)
+    std::vector<int> sv;
+  };
+}
+
+// Test eager-loaded, manually-updated section.
+//
+#pragma db namespace table("t5_")
+namespace test5
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : sn (n_), n (n_), ss (s_) {sv.push_back (n_);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db section(s)
+    int sn;
+
+    #pragma db update(manual)
+    odb::section s;
+
+    int n;
+
+    #pragma db section(s)
+    std::string ss;
+
+    #pragma db section(s)
+    std::vector<int> sv;
+  };
+}
+
+// Test value-only and container-only section. Also multiple sections
+// in an object.
+//
+#pragma db namespace table("t6_")
+namespace test6
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : n (n_), sn (n_), ss (s_) {sv.push_back (n_);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    int n;
+
+    #pragma db load(lazy)
+    odb::section s1;
+
+    #pragma db load(lazy)
+    odb::section s2;
+
+    #pragma db section(s1)
+    int sn;
+
+    #pragma db section(s1)
+    std::string ss;
+
+    #pragma db section(s2)
+    std::vector<int> sv;
+  };
+}
+
+// Test sections and reuse inheritance.
+//
+#pragma db namespace table("t7_")
+namespace test7
+{
+  #pragma db object abstract
+  struct base
+  {
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy)
+    odb::section s1; // Empty section.
+
+    #pragma db load(lazy)
+    odb::section s2;
+
+    #pragma db section(s2)
+    int sn2;
+  };
+
+  #pragma db object abstract
+  struct interm: base
+  {
+    // Section s1 is still empty.
+
+    #pragma db section(s2)
+    std::string ss2;
+  };
+
+  #pragma db object
+  struct derived: interm
+  {
+    #pragma db section(s1)
+    int sn1;
+  };
+
+  #pragma db object
+  struct object: derived
+  {
+    object (int n = 999, const std::string& s = "xxx", bool b = false)
+    {
+      sn1 = sn2 = n;
+      ss1 = ss2 = s;
+      sb2 = b;
+    }
+
+    #pragma db section(s1)
+    std::string ss1;
+
+    #pragma db section(s2)
+    bool sb2;
+  };
+}
+
+// Test readonly and inverse section members.
+//
+#pragma db namespace table("t8_")
+namespace test8
+{
+  struct object1;
+
+  #pragma db object session
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx", object1* p_ = 0)
+        : n (n_), sn (n_), ss (s_), sp (p_) {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    int n;
+
+    #pragma db load(lazy)
+    odb::section s;
+
+    #pragma db section(s) readonly
+    int sn;
+
+    #pragma db section(s)
+    std::string ss;
+
+    #pragma db inverse(p) section(s)
+    object1* sp;
+  };
+
+  #pragma db object session
+  struct object1
+  {
+    object1 (object* p_ = 0): p (p_) {}
+    ~object1 () {delete p;}
+
+    #pragma db id auto
+    unsigned long id;
+
+    object* p;
+  };
+}
+
+// Test object without any columns to load or update.
+//
+#pragma db namespace table("t9_")
+namespace test9
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx"): sn (n_), ss (s_) {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy) update(manual)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+
+    #pragma db section(s)
+    std::string ss;
+  };
+}
+
+// Test section without any columns or containers to update.
+//
+#pragma db namespace table("t10_")
+namespace test10
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999): n (n_), sn (n_) {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    int n;
+
+    #pragma db load(lazy)
+    odb::section s;
+
+    #pragma db section(s) readonly
+    int sn;
+  };
+}
+
+// Test section with composite member.
+//
+#pragma db namespace table("t11_")
+namespace test11
+{
+  #pragma db value
+  struct comp
+  {
+    comp (int n_, const std::string& s_): s (s_) {v.push_back (n_);}
+
+    std::string s;
+    std::vector<int> v;
+  };
+
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : n (n_), sn (n_), sc (n_, s_) {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    int n;
+
+    #pragma db load(lazy)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+
+    #pragma db section(s)
+    comp sc;
+  };
+}
+
+// Test change state restoration on transaction rollback.
+//
+#pragma db namespace table("t12_")
+namespace test12
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : sn (n_), n (n_), ss (s_) {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy) update(change)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+
+    int n;
+
+    #pragma db section(s)
+    std::string ss;
+  };
+}
+
+// Test section accessor/modifier.
+//
+#pragma db namespace table("t13_")
+namespace test13
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : n (n_), sn (n_), ss (s_) {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    int n;
+
+    #pragma db section(s_)
+    int sn;
+
+    #pragma db section(s_)
+    std::string ss;
+
+  public:
+    const odb::section&
+    s () const {return s_;}
+
+    odb::section&
+    rw_s () {return s_;}
+
+  private:
+    #pragma db load(lazy) update(manual)
+    odb::section s_;
+  };
+}
+
+// Test LOB in section streaming, column re-ordering.
+//
+#pragma db namespace table("t14_")
+namespace test14
+{
+  #pragma db object
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : sb (s_.begin (), s_.end ()), sn (n_), n (n_) {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy)
+    odb::section s;
+
+    #pragma db section(s) type(BLOB_TYPE)
+    std::vector<char> sb; // Comes before sn.
+
+    #pragma db section(s)
+    int sn;
+
+    int n;
+  };
+}
+
+// Test sections and optimistic concurrency.
+//
+#pragma db namespace table("t15_")
+namespace test15
+{
+  #pragma db object optimistic
+  struct object
+  {
+    object (int n_ = 999, const std::string& s_ = "xxx")
+        : sn (n_), n (n_), ss (s_) {sv.push_back (n_);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db version mssql:type("ROWVERSION")
+    unsigned long long v;
+
+    #pragma db load(lazy)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+
+    int n;
+
+    #pragma db section(s)
+    std::string ss;
+
+    #pragma db section(s)
+    std::vector<int> sv;
+  };
+}
+
+// Test container-only sections and optimistic concurrency.
+//
+#pragma db namespace table("t16_")
+namespace test16
+{
+  #pragma db object optimistic
+  struct object
+  {
+    object (int n = 999) {sv.push_back (n);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db version // mssql:type("ROWVERSION")
+    unsigned long long v;
+
+    #pragma db load(lazy)
+    odb::section s;
+
+    #pragma db section(s)
+    std::vector<int> sv;
+  };
+}
+
+// Test reuse-inheritance, sections, and optimistic concurrency.
+//
+#pragma db namespace table("t17_")
+namespace test17
+{
+  #pragma db object optimistic sectionable abstract
+  struct root
+  {
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db version
+    unsigned long long v;
+  };
+
+  #pragma db object
+  struct base: root
+  {
+  };
+
+  #pragma db object
+  struct object: base
+  {
+    object (int n = 999): s1n (n) {s2v.push_back (n);}
+
+    #pragma db load(lazy)
+    odb::section s1;
+
+    #pragma db section(s1)
+    int s1n;
+
+    #pragma db load(lazy)
+    odb::section s2;
+
+    #pragma db section(s2)
+    std::vector<int> s2v;
+  };
+}
+
+// Test change-updated section and change-tracking container.
+//
+#pragma db namespace table("t18_")
+namespace test18
+{
+  #pragma db object
+  struct object
+  {
+    object (int n = 999): sn (n) {sv.push_back (n);}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy) update(change)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+
+    #pragma db section(s)
+    odb::vector<int> sv;
+  };
+}
+
+#endif // TEST_HXX
diff --git a/common/section/basics/test.std b/common/section/basics/test.std
new file mode 100644
index 0000000..e69de29
diff --git a/common/section/polymorphism/driver.cxx b/common/section/polymorphism/driver.cxx
new file mode 100644
index 0000000..8c38035
--- /dev/null
+++ b/common/section/polymorphism/driver.cxx
@@ -0,0 +1,1763 @@
+// file      : common/section/polymorphism/driver.cxx
+// copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+// Test sections in polymorphic objects.
+//
+
+#include <memory>   // std::auto_ptr
+#include <cassert>
+#include <iostream>
+
+#include <odb/session.hxx>
+#include <odb/database.hxx>
+#include <odb/transaction.hxx>
+
+#include <common/common.hxx>
+
+#include "test.hxx"
+#include "test-odb.hxx"
+
+using namespace std;
+using namespace odb::core;
+
+struct failed {};
+
+int
+main (int argc, char* argv[])
+{
+  try
+  {
+    auto_ptr<database> db (create_database (argc, argv));
+
+    // Test basic polymorphic section functionality.
+    //
+    {
+      using namespace test1;
+
+      base b (123, "abc");
+      derived d (234, "bcd", true);
+
+      {
+        transaction t (db->begin ());
+        db->persist (b);
+        db->persist (d);
+        t.commit ();
+
+        assert (b.rs1.loaded ());
+        assert (b.rs2.loaded ());
+        assert (b.rs3.loaded ());
+        assert (b.rs4.loaded ());
+        assert (b.bs1.loaded ());
+
+        assert (d.rs1.loaded ());
+        assert (d.rs2.loaded ());
+        assert (d.rs3.loaded ());
+        assert (d.rs4.loaded ());
+        assert (d.bs1.loaded ());
+        assert (d.ds1.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        assert (!pb->rs1.loaded ());
+        assert (!pb->rs2.loaded ());
+        assert (!pb->rs3.loaded ());
+        assert (!pb->rs4.loaded ());
+        assert (!pb->bs1.loaded ());
+
+        assert (!pd->rs1.loaded ());
+        assert (!pd->rs2.loaded ());
+        assert (!pd->rs3.loaded ());
+        assert (!pd->rs4.loaded ());
+        assert (!pd->bs1.loaded ());
+        assert (!pd->ds1.loaded ());
+
+        assert (pb->rs1n != b.rs1n && pb->rs1s != b.rs1s &&
+                pb->rs2n != b.rs2n && pb->rs2v != b.rs2v &&
+                pb->rs3v != b.rs3v &&
+                pb->rs4n != b.rs4n &&
+                pb->bs1n != b.bs1n);
+
+        assert (pd->rs1n != d.rs1n && pd->rs1s != d.rs1s &&
+                  pd->rs1b != d.rs1b && pd->rs1v != d.rs1v &&
+                pd->rs2n != d.rs2n && pd->rs2v != d.rs2v &&
+                pd->rs3v != d.rs3v && pd->rs3n != d.rs3n &&
+                pd->rs4n != d.rs4n && pd->rs4s != d.rs4s &&
+                pd->bs1n != d.bs1n && pd->bs1s != d.bs1s &&
+                pd->ds1n != d.ds1n);
+
+        db->load (*pb, pb->rs1);
+        db->load (*pb, pb->rs2);
+        db->load (*pb, pb->rs3);
+        db->load (*pb, pb->rs4);
+        db->load (*pb, pb->bs1);
+
+        root* pr (pd.get ());
+        db->load (*pr, pr->rs1); // Via base.
+        db->load (*pd, pd->rs2);
+        db->load (*pr, pr->rs3); // Via base.
+        db->load (*pd, pd->rs4);
+        db->load (*pd, pd->bs1);
+        db->load (*pd, pd->ds1);
+
+        try
+        {
+          db->load (*pr, pd->bs1); // Object-section association is static.
+          assert (false);
+        }
+        catch (const section_not_in_object&) {}
+
+        assert (pb->rs1.loaded ());
+        assert (pb->rs2.loaded ());
+        assert (pb->rs3.loaded ());
+        assert (pb->rs4.loaded ());
+        assert (pb->bs1.loaded ());
+
+        assert (pd->rs1.loaded ());
+        assert (pd->rs2.loaded ());
+        assert (pd->rs3.loaded ());
+        assert (pd->rs4.loaded ());
+        assert (pd->bs1.loaded ());
+        assert (pd->ds1.loaded ());
+
+        assert (pb->rs1n == b.rs1n && pb->rs1s == b.rs1s &&
+                pb->rs2n == b.rs2n && pb->rs2v == b.rs2v &&
+                pb->rs3v == b.rs3v &&
+                pb->rs4n == b.rs4n &&
+                pb->bs1n == b.bs1n);
+
+        assert (pd->rs1n == d.rs1n && pd->rs1s == d.rs1s &&
+                  pd->rs1b == d.rs1b && pd->rs1v == d.rs1v &&
+                pd->rs2n == d.rs2n && pd->rs2v == d.rs2v &&
+                pd->rs3v == d.rs3v && pd->rs3n == d.rs3n &&
+                pd->rs4n == d.rs4n && pd->rs4s == d.rs4s &&
+                pd->bs1n == d.bs1n && pd->bs1s == d.bs1s &&
+                pd->ds1n == d.ds1n);
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      b.rs1n++;
+      b.rs1s += 'd';
+      b.rs1.change ();
+      b.rs2n++;
+      b.rs2v[0]++;
+      b.rs3v[0]++;
+      b.rs4n++;
+      b.bs1n++;
+
+      d.rs1n++;
+      d.rs1s += 'e';
+      d.rs1b = !d.rs1b;
+      d.rs1v[0]++;
+      d.rs1.change ();
+      d.rs2n++;
+      d.rs2v[0]++;
+      d.rs3v[0]++;
+      d.rs3n++;
+      d.rs4n++;
+      d.rs4s += 'e';
+      d.bs1n++;
+      d.bs1s += 'e';
+      d.ds1n++;
+
+      {
+        transaction t (db->begin ());
+        db->update (b);
+        db->update (d);
+        t.commit ();
+
+        assert (!b.rs1.changed ());
+        assert (!d.rs1.changed ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->load (*pb, pb->rs1);
+        db->load (*pb, pb->rs2);
+        db->load (*pb, pb->rs3);
+        db->load (*pb, pb->rs4);
+        db->load (*pb, pb->bs1);
+
+        db->load (*pd, pd->rs1);
+        db->load (*pd, pd->rs2);
+        db->load (*pd, pd->rs3);
+        db->load (*pd, pd->rs4);
+        db->load (*pd, pd->bs1);
+        db->load (*pd, pd->ds1);
+
+        assert (pb->rs1n == b.rs1n && pb->rs1s == b.rs1s &&
+                pb->rs2n == b.rs2n && pb->rs2v == b.rs2v &&
+                pb->rs3v == b.rs3v &&
+                pb->rs4n == b.rs4n &&
+                pb->bs1n == b.bs1n);
+
+        assert (pd->rs1n == d.rs1n && pd->rs1s == d.rs1s &&
+                  pd->rs1b == d.rs1b && pd->rs1v == d.rs1v &&
+                pd->rs2n == d.rs2n && pd->rs2v == d.rs2v &&
+                pd->rs3v == d.rs3v && pd->rs3n == d.rs3n &&
+                pd->rs4n == d.rs4n && pd->rs4s == d.rs4s &&
+                pd->bs1n == d.bs1n && pd->bs1s == d.bs1s &&
+                pd->ds1n == d.ds1n);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      b.rs1n++;
+      b.rs1s += 'd';
+      b.rs2n++;
+      b.rs2v[0]++;
+      b.rs3v[0]++;
+      b.rs4n++;
+      b.bs1n++;
+
+      d.rs1n++;
+      d.rs1s += 'e';
+      d.rs1b = !d.rs1b;
+      d.rs1v[0]++;
+      d.rs2n++;
+      d.rs2v[0]++;
+      d.rs3v[0]++;
+      d.rs3n++;
+      d.rs4n++;
+      d.rs4s += 'e';
+      d.bs1n++;
+      d.bs1s += 'e';
+      d.ds1n++;
+
+      {
+        transaction t (db->begin ());
+        db->update (b, b.rs1);
+        db->update (b, b.rs2);
+        db->update (b, b.rs3);
+        db->update (b, b.rs4);
+        db->update (b, b.bs1);
+
+        db->update (d, d.rs1);
+        db->update (d, d.rs2);
+        db->update (d, d.rs3);
+        db->update (d, d.rs4);
+        db->update (d, d.bs1);
+        db->update (d, d.ds1);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->load (*pb, pb->rs1);
+        db->load (*pb, pb->rs2);
+        db->load (*pb, pb->rs3);
+        db->load (*pb, pb->rs4);
+        db->load (*pb, pb->bs1);
+
+        db->load (*pd, pd->rs1);
+        db->load (*pd, pd->rs2);
+        db->load (*pd, pd->rs3);
+        db->load (*pd, pd->rs4);
+        db->load (*pd, pd->bs1);
+        db->load (*pd, pd->ds1);
+
+        assert (pb->rs1n == b.rs1n && pb->rs1s == b.rs1s &&
+                pb->rs2n == b.rs2n && pb->rs2v == b.rs2v &&
+                pb->rs3v == b.rs3v &&
+                pb->rs4n == b.rs4n &&
+                pb->bs1n == b.bs1n);
+
+        assert (pd->rs1n == d.rs1n && pd->rs1s == d.rs1s &&
+                  pd->rs1b == d.rs1b && pd->rs1v == d.rs1v &&
+                pd->rs2n == d.rs2n && pd->rs2v == d.rs2v &&
+                pd->rs3v == d.rs3v && pd->rs3n == d.rs3n &&
+                pd->rs4n == d.rs4n && pd->rs4s == d.rs4s &&
+                pd->bs1n == d.bs1n && pd->bs1s == d.bs1s &&
+                pd->ds1n == d.ds1n);
+        t.commit ();
+      }
+
+      // Reload.
+      //
+      b.rs1n++;
+      b.rs1s += 'd';
+      b.rs1.change ();
+      b.rs2n++;
+      b.rs2v[0]++;
+      b.rs3v[0]++;
+      b.rs4n++;
+      b.bs1n++;
+
+      d.rs1n++;
+      d.rs1s += 'e';
+      d.rs1b = !d.rs1b;
+      d.rs1v[0]++;
+      d.rs1.change ();
+      d.rs2n++;
+      d.rs2v[0]++;
+      d.rs3v[0]++;
+      d.rs3n++;
+      d.rs4n++;
+      d.rs4s += 'e';
+      d.bs1n++;
+      d.bs1s += 'e';
+      d.ds1n++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->load (*pb, pb->rs1);
+        db->load (*pb, pb->rs2);
+        db->load (*pb, pb->rs3);
+        db->load (*pb, pb->rs4);
+        db->load (*pb, pb->bs1);
+
+        db->load (*pd, pd->rs1);
+        db->load (*pd, pd->rs2);
+        db->load (*pd, pd->rs3);
+        db->load (*pd, pd->rs4);
+        db->load (*pd, pd->bs1);
+        db->load (*pd, pd->ds1);
+
+        db->update (b);
+        db->update (d);
+
+        db->reload (*pb);
+        db->reload (*pd);
+
+        assert (pb->rs1n == b.rs1n && pb->rs1s == b.rs1s &&
+                pb->rs2n == b.rs2n && pb->rs2v == b.rs2v &&
+                pb->rs3v == b.rs3v &&
+                pb->rs4n == b.rs4n &&
+                pb->bs1n == b.bs1n);
+
+        assert (pd->rs1n == d.rs1n && pd->rs1s == d.rs1s &&
+                  pd->rs1b == d.rs1b && pd->rs1v == d.rs1v &&
+                pd->rs2n == d.rs2n && pd->rs2v == d.rs2v &&
+                pd->rs3v == d.rs3v && pd->rs3n == d.rs3n &&
+                pd->rs4n == d.rs4n && pd->rs4s == d.rs4s &&
+                pd->bs1n == d.bs1n && pd->bs1s == d.bs1s &&
+                pd->ds1n == d.ds1n);
+
+        t.commit ();
+      }
+    }
+
+    // Test empty section and override "gap".
+    //
+    {
+      using namespace test2;
+
+      derived d (234);
+
+      {
+        transaction t (db->begin ());
+        db->persist (d);
+        t.commit ();
+
+        assert (d.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        assert (!pd->s.loaded ());
+        assert (pd->sn != d.sn && pd->sv != d.sv);
+
+        root* pr (pd.get ());
+        db->load (*pr, pr->s); // Via root.
+
+        assert (pd->s.loaded ());
+        assert (pd->sn == d.sn && pd->sv == d.sv);
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      d.sn++;
+      d.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        root* pr (&d);
+        db->update (pr); // Via root.
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        base* pb (pd.get ());
+        db->load (*pb, pb->s); // Via base.
+
+        assert (pd->sn == d.sn && pd->sv == d.sv);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      d.sn++;
+      d.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        root* pr (&d);
+        db->update (*pr, pr->s); // Via root.
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->load (*pd, pd->s);
+
+        assert (pd->sn == d.sn && pd->sv == d.sv);
+        t.commit ();
+      }
+
+      // Reload.
+      //
+      d.sn++;
+      d.sv[0]++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->load (*pd, pd->s);
+
+        db->update (d);
+
+        root* pr (pd.get ());
+        db->reload (*pr);
+
+        assert (pd->sn == d.sn && pd->sv == d.sv);
+        t.commit ();
+      }
+    }
+
+    // Test value-only/container-only base/override combinations.
+    //
+    {
+      using namespace test3;
+
+      root r (123);
+      base b (234);
+      derived d (345, "abc");
+
+      {
+        transaction t (db->begin ());
+        db->persist (r);
+        db->persist (b);
+        db->persist (d);
+        t.commit ();
+
+        assert (r.s1.loaded ());
+        assert (r.s2.loaded ());
+        assert (r.s3.loaded ());
+        assert (r.s4.loaded ());
+
+        assert (b.s1.loaded ());
+        assert (b.s2.loaded ());
+        assert (b.s3.loaded ());
+        assert (b.s4.loaded ());
+
+        assert (d.s1.loaded ());
+        assert (d.s2.loaded ());
+        assert (d.s3.loaded ());
+        assert (d.s4.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<root> pr (db->load<root> (r.id));
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        assert (!pr->s1.loaded ());
+        assert (!pr->s2.loaded ());
+        assert (!pr->s3.loaded ());
+        assert (!pr->s4.loaded ());
+
+        assert (!pb->s1.loaded ());
+        assert (!pb->s2.loaded ());
+        assert (!pb->s3.loaded ());
+        assert (!pb->s4.loaded ());
+
+        assert (!pd->s1.loaded ());
+        assert (!pd->s2.loaded ());
+        assert (!pd->s3.loaded ());
+        assert (!pd->s4.loaded ());
+
+        assert (pr->s1n != r.s1n &&
+                pr->s2n != r.s2n &&
+                pr->s3v != r.s3v &&
+                pr->s4nv != r.s4nv);
+
+        assert (pb->s1n != b.s1n &&
+                pb->s2n != b.s2n &&
+                pb->s3v != b.s3v &&
+                pb->s4nv != b.s4nv);
+
+        assert (pd->s1n != d.s1n && pd->s1s != d.s1s &&
+                pd->s2n != d.s2n && pd->s2v != d.s2v &&
+                pd->s3v != d.s3v && pd->s3n != d.s3n &&
+                pd->s4nv != d.s4nv && pd->s4sv != d.s4sv);
+
+        db->load (*pr, pr->s1);
+        db->load (*pr, pr->s2);
+        db->load (*pr, pr->s3);
+        db->load (*pr, pr->s4);
+
+        db->load (*pb, pb->s1);
+        db->load (*pb, pb->s2);
+        db->load (*pb, pb->s3);
+        db->load (*pb, pb->s4);
+
+        root* pdr (pd.get ());
+        db->load (*pdr, pdr->s1);
+        db->load (*pdr, pdr->s2);
+        db->load (*pdr, pdr->s3);
+        db->load (*pdr, pdr->s4);
+
+        assert (pr->s1.loaded ());
+        assert (pr->s2.loaded ());
+        assert (pr->s3.loaded ());
+        assert (pr->s4.loaded ());
+
+        assert (pb->s1.loaded ());
+        assert (pb->s2.loaded ());
+        assert (pb->s3.loaded ());
+        assert (pb->s4.loaded ());
+
+        assert (pd->s1.loaded ());
+        assert (pd->s2.loaded ());
+        assert (pd->s3.loaded ());
+        assert (pd->s4.loaded ());
+
+        assert (pr->s1n == r.s1n &&
+                pr->s2n == r.s2n &&
+                pr->s3v == r.s3v &&
+                pr->s4nv == r.s4nv);
+
+        assert (pb->s1n == b.s1n &&
+                pb->s2n == b.s2n &&
+                pb->s3v == b.s3v &&
+                pb->s4nv == b.s4nv);
+
+        assert (pd->s1n == d.s1n && pd->s1s == d.s1s &&
+                pd->s2n == d.s2n && pd->s2v == d.s2v &&
+                pd->s3v == d.s3v && pd->s3n == d.s3n &&
+                pd->s4nv == d.s4nv && pd->s4sv == d.s4sv);
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      r.s1n++;
+      r.s2n++;
+      r.s3v[0]++;
+      r.s4nv[0]++;
+
+      b.s1n++;
+      b.s2n++;
+      b.s3v[0]++;
+      b.s4nv[0]++;
+
+      d.s1n++;
+      d.s1s += 'd';
+      d.s2n++;
+      d.s2v[0]++;
+      d.s3v[0]++;
+      d.s3n++;
+      d.s4nv[0]++;
+      d.s4sv[0] += 'd';
+
+      {
+        transaction t (db->begin ());
+        db->update (r);
+        db->update (b);
+        db->update (d);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<root> pr (db->load<root> (r.id));
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->load (*pr, pr->s1);
+        db->load (*pr, pr->s2);
+        db->load (*pr, pr->s3);
+        db->load (*pr, pr->s4);
+
+        db->load (*pb, pb->s1);
+        db->load (*pb, pb->s2);
+        db->load (*pb, pb->s3);
+        db->load (*pb, pb->s4);
+
+        db->load (*pd, pd->s1);
+        db->load (*pd, pd->s2);
+        db->load (*pd, pd->s3);
+        db->load (*pd, pd->s4);
+
+        assert (pr->s1n == r.s1n &&
+                pr->s2n == r.s2n &&
+                pr->s3v == r.s3v &&
+                pr->s4nv == r.s4nv);
+
+        assert (pb->s1n == b.s1n &&
+                pb->s2n == b.s2n &&
+                pb->s3v == b.s3v &&
+                pb->s4nv == b.s4nv);
+
+        assert (pd->s1n == d.s1n && pd->s1s == d.s1s &&
+                pd->s2n == d.s2n && pd->s2v == d.s2v &&
+                pd->s3v == d.s3v && pd->s3n == d.s3n &&
+                pd->s4nv == d.s4nv && pd->s4sv == d.s4sv);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      r.s1n++;
+      r.s2n++;
+      r.s3v[0]++;
+      r.s4nv[0]++;
+
+      b.s1n++;
+      b.s2n++;
+      b.s3v[0]++;
+      b.s4nv[0]++;
+
+      d.s1n++;
+      d.s1s += 'd';
+      d.s2n++;
+      d.s2v[0]++;
+      d.s3v[0]++;
+      d.s3n++;
+      d.s4nv[0]++;
+      d.s4sv[0] += 'd';
+
+      {
+        transaction t (db->begin ());
+        db->update (r, r.s1);
+        db->update (r, r.s2);
+        db->update (r, r.s3);
+        db->update (r, r.s4);
+
+        db->update (b, b.s1);
+        db->update (b, b.s2);
+        db->update (b, b.s3);
+        db->update (b, b.s4);
+
+        root& rr (d);
+        db->update (rr, rr.s1);
+        db->update (rr, rr.s2);
+        db->update (rr, rr.s3);
+        db->update (rr, rr.s4);
+        t.commit ();
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<root> pr (db->load<root> (r.id));
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->load (*pr, pr->s1);
+        db->load (*pr, pr->s2);
+        db->load (*pr, pr->s3);
+        db->load (*pr, pr->s4);
+
+        db->load (*pb, pb->s1);
+        db->load (*pb, pb->s2);
+        db->load (*pb, pb->s3);
+        db->load (*pb, pb->s4);
+
+        db->load (*pd, pd->s1);
+        db->load (*pd, pd->s2);
+        db->load (*pd, pd->s3);
+        db->load (*pd, pd->s4);
+
+        assert (pr->s1n == r.s1n &&
+                pr->s2n == r.s2n &&
+                pr->s3v == r.s3v &&
+                pr->s4nv == r.s4nv);
+
+        assert (pb->s1n == b.s1n &&
+                pb->s2n == b.s2n &&
+                pb->s3v == b.s3v &&
+                pb->s4nv == b.s4nv);
+
+        assert (pd->s1n == d.s1n && pd->s1s == d.s1s &&
+                pd->s2n == d.s2n && pd->s2v == d.s2v &&
+                pd->s3v == d.s3v && pd->s3n == d.s3n &&
+                pd->s4nv == d.s4nv && pd->s4sv == d.s4sv);
+        t.commit ();
+      }
+
+      // Reload.
+      //
+      r.s1n++;
+      r.s2n++;
+      r.s3v[0]++;
+      r.s4nv[0]++;
+
+      b.s1n++;
+      b.s2n++;
+      b.s3v[0]++;
+      b.s4nv[0]++;
+
+      d.s1n++;
+      d.s1s += 'd';
+      d.s2n++;
+      d.s2v[0]++;
+      d.s3v[0]++;
+      d.s3n++;
+      d.s4nv[0]++;
+      d.s4sv[0] += 'd';
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<root> pr (db->load<root> (r.id));
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->load (*pr, pr->s1);
+        db->load (*pr, pr->s2);
+        db->load (*pr, pr->s3);
+        db->load (*pr, pr->s4);
+
+        db->load (*pb, pb->s1);
+        db->load (*pb, pb->s2);
+        db->load (*pb, pb->s3);
+        db->load (*pb, pb->s4);
+
+        db->load (*pd, pd->s1);
+        db->load (*pd, pd->s2);
+        db->load (*pd, pd->s3);
+        db->load (*pd, pd->s4);
+
+        db->update (r);
+        db->update (b);
+        db->update (d);
+
+        db->reload (*pr);
+        db->reload (*pb);
+        db->reload (*pd);
+
+        assert (pr->s1n == r.s1n &&
+                pr->s2n == r.s2n &&
+                pr->s3v == r.s3v &&
+                pr->s4nv == r.s4nv);
+
+        assert (pb->s1n == b.s1n &&
+                pb->s2n == b.s2n &&
+                pb->s3v == b.s3v &&
+                pb->s4nv == b.s4nv);
+
+        assert (pd->s1n == d.s1n && pd->s1s == d.s1s &&
+                pd->s2n == d.s2n && pd->s2v == d.s2v &&
+                pd->s3v == d.s3v && pd->s3n == d.s3n &&
+                pd->s4nv == d.s4nv && pd->s4sv == d.s4sv);
+        t.commit ();
+      }
+    }
+
+    // Test basic polymorphic optimistic section functionality.
+    //
+    {
+      using namespace test4;
+
+      base b (123, "abc");
+      derived d (234, "bcd", true);
+
+      {
+        transaction t (db->begin ());
+        db->persist (b);
+        db->persist (d);
+        t.commit ();
+
+        assert (b.rs1.loaded ());
+        assert (b.rs2.loaded ());
+        assert (b.rs3.loaded ());
+        assert (b.rs4.loaded ());
+        assert (b.bs1.loaded ());
+
+        assert (d.rs1.loaded ());
+        assert (d.rs2.loaded ());
+        assert (d.rs3.loaded ());
+        assert (d.rs4.loaded ());
+        assert (d.bs1.loaded ());
+        assert (d.ds1.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        assert (!pb->rs1.loaded ());
+        assert (!pb->rs2.loaded ());
+        assert (!pb->rs3.loaded ());
+        assert (!pb->rs4.loaded ());
+        assert (!pb->bs1.loaded ());
+
+        assert (!pd->rs1.loaded ());
+        assert (!pd->rs2.loaded ());
+        assert (!pd->rs3.loaded ());
+        assert (!pd->rs4.loaded ());
+        assert (!pd->bs1.loaded ());
+        assert (!pd->ds1.loaded ());
+
+        assert (pb->rs1n != b.rs1n && pb->rs1s != b.rs1s &&
+                pb->rs2n != b.rs2n &&
+                pb->rs3n != b.rs3n &&
+                pb->rs4n != b.rs4n && pb->rs4s != b.rs4s);
+
+        assert (pd->rs1n != d.rs1n && pd->rs1s != d.rs1s &&
+                  pd->rs1b != d.rs1b && pd->rs1v != d.rs1v &&
+                pd->rs2n != d.rs2n &&
+                pd->rs3n != d.rs3n && pd->rs3s != d.rs3s &&
+                pd->rs4n != d.rs4n && pd->rs4s != d.rs4s &&
+                  pd->rs4v != d.rs4v &&
+                pd->bs1n != d.bs1n &&
+                pd->ds1v != d.ds1v);
+
+        db->load (*pb, pb->rs1);
+        db->load (*pb, pb->rs2);
+        db->load (*pb, pb->rs3);
+        db->load (*pb, pb->rs4);
+        db->load (*pb, pb->bs1); // No-op.
+
+        root* pr (pd.get ());
+        db->load (*pr, pr->rs1); // Via base.
+        db->load (*pd, pd->rs2);
+        db->load (*pd, pd->rs3);
+        db->load (*pr, pr->rs4); // Via base.
+        db->load (*pd, pd->bs1);
+        db->load (*pd, pd->ds1);
+
+        assert (pb->rs1.loaded ());
+        assert (pb->rs2.loaded ());
+        assert (pb->rs3.loaded ());
+        assert (pb->rs4.loaded ());
+        assert (pb->bs1.loaded ());
+
+        assert (pd->rs1.loaded ());
+        assert (pd->rs2.loaded ());
+        assert (pd->rs3.loaded ());
+        assert (pd->rs4.loaded ());
+        assert (pd->bs1.loaded ());
+        assert (pd->ds1.loaded ());
+
+        assert (pb->rs1n == b.rs1n && pb->rs1s == b.rs1s &&
+                pb->rs2n == b.rs2n &&
+                pb->rs3n == b.rs3n &&
+                pb->rs4n == b.rs4n && pb->rs4s == b.rs4s);
+
+        assert (pd->rs1n == d.rs1n && pd->rs1s == d.rs1s &&
+                  pd->rs1b == d.rs1b && pd->rs1v == d.rs1v &&
+                pd->rs2n == d.rs2n &&
+                pd->rs3n == d.rs3n && pd->rs3s == d.rs3s &&
+                pd->rs4n == d.rs4n && pd->rs4s == d.rs4s &&
+                  pd->rs4v == d.rs4v &&
+                pd->bs1n == d.bs1n &&
+                pd->ds1v == d.ds1v);
+        t.commit ();
+      }
+
+      base b1 (b);
+      derived d1 (d);
+
+      // Update object.
+      //
+      for (unsigned short s (1); s < 7; ++s)
+      {
+        b1.rs1n++;
+        b1.rs1s += 'd';
+        b1.rs1.change ();
+        b1.rs4s += 'd';
+
+        d1.rs1n++;
+        d1.rs1s += 'e';
+        d1.rs1b = !d.rs1b;
+        d1.rs1v[0]++;
+        d1.rs1.change ();
+        d1.rs4s += 'e';
+        d1.rs4v[0]++;
+        d1.bs1n++;
+        d1.ds1v[0]++;
+
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->update (b1);
+        db->update (d1);
+
+        assert (!b1.rs1.changed ());
+        assert (!d1.rs1.changed ());
+
+        assert (b.v != b1.v);
+        assert (d.v != d1.v);
+
+        try
+        {
+          bool a (false);
+          switch (s)
+          {
+          case 1: db->load (*pb, pb->rs1); break;
+          case 2: db->load (*pb, pb->rs2); break;
+          case 3: db->load (*pb, pb->rs3); break;
+          case 4: db->load (*pb, pb->rs4); break;
+          case 5:
+          case 6: a = true; break; // No-op.
+          default: break;
+          }
+          assert (a);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pb);
+
+          assert (!pb->rs1.loaded ());
+          assert (!pb->rs2.loaded ());
+          assert (!pb->rs3.loaded ());
+          assert (!pb->rs3.loaded ());
+          assert (!pb->bs1.loaded ());
+
+          db->load (*pb, pb->rs1);
+          db->load (*pb, pb->rs2);
+          db->load (*pb, pb->rs3);
+          db->load (*pb, pb->rs4);
+          db->load (*pb, pb->bs1); // No-op.
+
+          assert (pb->rs1n == b1.rs1n && pb->rs1s == b1.rs1s &&
+                  pb->rs2n == b1.rs2n &&
+                  pb->rs3n == b1.rs3n &&
+                  pb->rs4n == b1.rs4n && pb->rs4s == b1.rs4s);
+        }
+
+        try
+        {
+          switch (s)
+          {
+          case 1: db->load (*pd, pd->rs1); break;
+          case 2: db->load (*pd, pd->rs2); break;
+          case 3: db->load (*pd, pd->rs3); break;
+          case 4: db->load (*pd, pd->rs4); break;
+          case 5: db->load (*pd, pd->bs1); break;
+          case 6: db->load (*pd, pd->ds1); break;
+          default: break;
+          }
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pd);
+
+          assert (!pd->rs1.loaded ());
+          assert (!pd->rs2.loaded ());
+          assert (!pd->rs3.loaded ());
+          assert (!pd->rs4.loaded ());
+          assert (!pd->bs1.loaded ());
+          assert (!pd->ds1.loaded ());
+
+          db->load (*pd, pd->rs1);
+          db->load (*pd, pd->rs2);
+          db->load (*pd, pd->rs3);
+          db->load (*pd, pd->rs4);
+          db->load (*pd, pd->bs1);
+          db->load (*pd, pd->ds1);
+
+          assert (pd->rs1n == d1.rs1n && pd->rs1s == d1.rs1s &&
+                    pd->rs1b == d1.rs1b && pd->rs1v == d1.rs1v &&
+                  pd->rs2n == d1.rs2n &&
+                  pd->rs3n == d1.rs3n && pd->rs3s == d1.rs3s &&
+                  pd->rs4n == d1.rs4n && pd->rs4s == d1.rs4s &&
+                    pd->rs4v == d1.rs4v &&
+                  pd->bs1n == d1.bs1n &&
+                  pd->ds1v == d1.ds1v);
+        }
+
+        db->reload (b);
+        db->reload (d);
+
+        assert (b.v == b1.v);
+        assert (d.v == d1.v);
+
+        assert (b.rs1n == b1.rs1n && b.rs1s == b1.rs1s &&
+                b.rs2n == b1.rs2n &&
+                b.rs3n == b1.rs3n &&
+                b.rs4n == b1.rs4n && b.rs4s == b1.rs4s);
+
+        assert (d.rs1n == d1.rs1n && d.rs1s == d1.rs1s &&
+                  d.rs1b == d1.rs1b && d.rs1v == d1.rs1v &&
+                d.rs2n == d1.rs2n &&
+                d.rs3n == d1.rs3n && d.rs3s == d1.rs3s &&
+                d.rs4n == d1.rs4n && d.rs4s == d1.rs4s &&
+                  d.rs4v == d1.rs4v &&
+                d.bs1n == d1.bs1n &&
+                d.ds1v == d1.ds1v);
+
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      for (unsigned short s (1); s < 7; ++s)
+      {
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        switch (s)
+        {
+        case 1:
+          b1.rs1n++;
+          b1.rs1s += 'd';
+
+          d1.rs1n++;
+          d1.rs1s += 'e';
+          d1.rs1b = !d.rs1b;
+          d1.rs1v[0]++;
+
+          db->update (b1, b1.rs1);
+          db->update (d1, d1.rs1);
+
+          assert (b.v != b1.v);
+          assert (d.v != d1.v);
+          break;
+        case 2:
+          db->update (b1, b1.rs2); // No-op.
+          db->update (d1, d1.rs2); // No-op.
+
+          assert (b.v == b1.v);
+          assert (d.v == d1.v);
+          continue; // Object hasn't changed.
+        case 3:
+          db->update (b1, b1.rs3); // No-op.
+          db->update (d1, d1.rs3); // No-op.
+
+          assert (b.v == b1.v);
+          assert (d.v == d1.v);
+          continue; // Object hasn't changed.
+        case 4:
+          b1.rs4s += 'd';
+
+          d1.rs4s += 'e';
+          d1.rs4v[0]++;
+
+          db->update (b1, b1.rs4);
+          db->update (d1, d1.rs4);
+
+          assert (b.v != b1.v);
+          assert (d.v != d1.v);
+          break;
+        case 5:
+          d1.bs1n++;
+
+          db->update (b1, b1.bs1); // No-op.
+          db->update (d1, d1.bs1);
+
+          assert (b.v == b1.v);
+          assert (d.v != d1.v);
+          break;
+        case 6:
+          d1.ds1v[0]++;
+
+          db->update (d1, d1.ds1);
+
+          assert (d.v != d1.v);
+          break;
+        default: break;
+        }
+
+        try
+        {
+          bool a (false);
+          switch (s)
+          {
+          case 1: db->load (*pb, pb->rs1); break;
+          case 4: db->load (*pb, pb->rs4); break;
+          case 5:
+          case 6: a = true; break; // No-op.
+          default: break;
+          }
+          assert (a);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pb);
+
+          assert (!pb->rs1.loaded ());
+          assert (!pb->rs2.loaded ());
+          assert (!pb->rs3.loaded ());
+          assert (!pb->rs4.loaded ());
+          assert (!pb->bs1.loaded ());
+
+          db->load (*pb, pb->rs1);
+          db->load (*pb, pb->rs2);
+          db->load (*pb, pb->rs3);
+          db->load (*pb, pb->rs4);
+          db->load (*pb, pb->bs1); // No-op.
+
+          assert (pb->rs1n == b1.rs1n && pb->rs1s == b1.rs1s &&
+                  pb->rs2n == b1.rs2n &&
+                  pb->rs3n == b1.rs3n &&
+                  pb->rs4n == b1.rs4n && pb->rs4s == b1.rs4s);
+        }
+
+        try
+        {
+          switch (s)
+          {
+          case 1: db->load (*pd, pd->rs1); break;
+          case 4: db->load (*pd, pd->rs4); break;
+          case 5: db->load (*pd, pd->bs1); break;
+          case 6: db->load (*pd, pd->ds1); break;
+          default: break;
+          }
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pd);
+
+          assert (!pd->rs1.loaded ());
+          assert (!pd->rs2.loaded ());
+          assert (!pd->rs3.loaded ());
+          assert (!pd->rs4.loaded ());
+          assert (!pd->bs1.loaded ());
+          assert (!pd->ds1.loaded ());
+
+          db->load (*pd, pd->rs1);
+          db->load (*pd, pd->rs2);
+          db->load (*pd, pd->rs3);
+          db->load (*pd, pd->rs4);
+          db->load (*pd, pd->bs1);
+          db->load (*pd, pd->ds1);
+
+          assert (pd->rs1n == d1.rs1n && pd->rs1s == d1.rs1s &&
+                    pd->rs1b == d1.rs1b && pd->rs1v == d1.rs1v &&
+                  pd->rs2n == d1.rs2n &&
+                  pd->rs3n == d1.rs3n && pd->rs3s == d1.rs3s &&
+                  pd->rs4n == d1.rs4n && pd->rs4s == d1.rs4s &&
+                    pd->rs4v == d1.rs4v &&
+                  pd->bs1n == d1.bs1n &&
+                  pd->ds1v == d1.ds1v);
+        }
+
+        db->reload (b);
+        db->reload (d);
+
+        assert (b.v == b1.v);
+        assert (d.v == d1.v);
+
+        assert (b.rs1n == b1.rs1n && b.rs1s == b1.rs1s &&
+                b.rs2n == b1.rs2n &&
+                b.rs3n == b1.rs3n &&
+                b.rs4n == b1.rs4n && b.rs4s == b1.rs4s);
+
+        assert (d.rs1n == d1.rs1n && d.rs1s == d1.rs1s &&
+                  d.rs1b == d1.rs1b && d.rs1v == d1.rs1v &&
+                d.rs2n == d1.rs2n &&
+                d.rs3n == d1.rs3n && d.rs3s == d1.rs3s &&
+                d.rs4n == d1.rs4n && d.rs4s == d1.rs4s &&
+                  d.rs4v == d1.rs4v &&
+                d.bs1n == d1.bs1n &&
+                d.ds1v == d1.ds1v);
+
+        t.commit ();
+      }
+
+      // Update changed section.
+      //
+      for (unsigned short s (1); s < 7; ++s)
+      {
+        if (s == 2 || s == 3) // Readonly sections.
+          continue;
+
+        transaction t (db->begin ());
+
+        switch (s)
+        {
+        case 1:
+          b1.rs1n++;
+          b1.rs1s += 'd';
+
+          d1.rs1n++;
+          d1.rs1s += 'e';
+          d1.rs1b = !d.rs1b;
+          d1.rs1v[0]++;
+
+          db->update (b1, b1.rs1);
+          db->update (d1, d1.rs1);
+          break;
+        case 4:
+          b1.rs4s += 'd';
+
+          d1.rs4s += 'e';
+          d1.rs4v[0]++;
+
+          db->update (b1, b1.rs4);
+          db->update (d1, d1.rs4);
+          break;
+        case 5:
+          d1.bs1n++;
+
+          db->update (b1, b1.bs1); // No-op.
+          db->update (d1, d1.bs1);
+          break;
+        case 6:
+          d1.ds1v[0]++;
+
+          db->update (d1, d1.bs1);
+          break;
+        default: break;
+        }
+
+        try
+        {
+          bool a (false);
+          switch (s)
+          {
+          case 1: db->update (b, b.rs1); break;
+          case 4: db->update (b, b.rs4); break;
+          case 5:
+          case 6: a = true; break; // No-op.
+          default: break;
+          }
+          assert (a);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (b);
+
+          switch (s)
+          {
+          case 1: db->update (b, b.rs1); break;
+          case 4: db->update (b, b.rs4); break;
+          default: break;
+          }
+        }
+
+        try
+        {
+          switch (s)
+          {
+          case 1: db->update (d, d.rs1); break;
+          case 4: db->update (d, d.rs4); break;
+          case 5: db->update (d, d.bs1); break;
+          case 6: db->update (d, d.ds1); break;
+          default: break;
+          }
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (d);
+
+          switch (s)
+          {
+          case 1: db->update (d, d.rs1); break;
+          case 4: db->update (d, d.rs4); break;
+          case 5: db->update (d, d.bs1); break;
+          case 6: db->update (d, d.ds1); break;
+          default: break;
+          }
+        }
+
+        db->reload (b1);
+        db->reload (d1);
+
+        t.commit ();
+      }
+    }
+
+    // Test polymorphic optimistic readonly/empty to readwrite section
+    // override.
+    //
+    {
+      using namespace test5;
+
+      base b;
+      derived d (123);
+
+      {
+        transaction t (db->begin ());
+        db->persist (b);
+        db->persist (d);
+        t.commit ();
+
+        assert (b.s.loaded ());
+        assert (d.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        assert (!pb->s.loaded ());
+        assert (!pd->s.loaded ());
+        assert (pd->sn != d.sn);
+
+        db->load (*pb, pb->s); // No-op.
+        db->load (*pd, pd->s);
+
+        assert (pb->s.loaded ());
+        assert (pd->s.loaded ());
+
+        assert (pd->sn == d.sn);
+
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      base b1 (b);
+      derived d1 (d);
+      d1.sn++;
+      d1.s.change ();
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->update (d1);
+
+        assert (!d1.s.changed ());
+        assert (d.v != d1.v);
+
+        try
+        {
+          db->load (*pd, pd->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pd);
+          assert (!pd->s.loaded ());
+          db->load (*pd, pd->s);
+          assert (pd->sn == d1.sn);
+        }
+
+        db->reload (d);
+        assert (d.v == d1.v);
+        assert (d.sn == d1.sn);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      d1.sn++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->update (b1, b1.s); // No-op.
+        db->update (d1, d1.s);
+
+        assert (b.v == b1.v);
+        assert (d.v != d1.v);
+
+        try
+        {
+          db->load (*pd, pd->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pd);
+          assert (!pd->s.loaded ());
+          db->load (*pd, pd->s);
+
+          assert (pd->sn == d1.sn);
+        }
+
+        db->reload (d);
+        assert (d.v == d1.v);
+        assert (d.sn == d1.sn);
+        t.commit ();
+      }
+
+      // Update changed section.
+      //
+      d1.sn++;
+
+      {
+        transaction t (db->begin ());
+        db->update (d1, d1.s);
+
+        try
+        {
+          db->update (d, d.s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (d);
+          db->update (d, d.s);
+        }
+
+        t.commit ();
+      }
+    }
+
+    // Test polymorphic optimistic readonly/empty to readwrite section
+    // override, eager-loaded case.
+    //
+    {
+      using namespace test6;
+
+      derived d (123);
+
+      {
+        transaction t (db->begin ());
+        db->persist (d);
+        t.commit ();
+
+        assert (d.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        assert (pd->s.loaded ());
+        assert (pd->sn == d.sn);
+
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      derived d1 (d);
+      d1.sn++;
+      d1.s.change ();
+
+      {
+        transaction t (db->begin ());
+
+        db->update (d1);
+
+        assert (!d1.s.changed ());
+        assert (d.v != d1.v);
+
+        db->reload (d);
+        assert (d.v == d1.v);
+        assert (d.sn == d1.sn);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      d1.sn++;
+
+      {
+        transaction t (db->begin ());
+
+        db->update (d1, d1.s);
+        assert (d.v != d1.v);
+
+        db->reload (d);
+        assert (d.v == d1.v);
+        assert (d.sn == d1.sn);
+        t.commit ();
+      }
+
+      // Update changed section.
+      //
+      d1.sn++;
+
+      {
+        transaction t (db->begin ());
+        db->update (d1, d1.s);
+
+        try
+        {
+          db->update (d, d.s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (d);
+          db->update (d, d.s);
+        }
+
+        t.commit ();
+      }
+    }
+
+    // Test polymorphic optimistic section added in derived.
+    //
+    {
+      using namespace test7;
+
+      base b;
+      derived d (123);
+
+      {
+        transaction t (db->begin ());
+        db->persist (b);
+        db->persist (d);
+        t.commit ();
+
+        assert (b.s.loaded ());
+        assert (d.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<base> pb (db->load<base> (b.id));
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        assert (!pb->s.loaded ());
+        assert (!pd->s.loaded ());
+        assert (pd->sn != d.sn);
+
+        db->load (*pb, pb->s); // No-op.
+        db->load (*pd, pd->s);
+
+        assert (pb->s.loaded ());
+        assert (pd->s.loaded ());
+
+        assert (pd->sn == d.sn);
+
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      base b1 (b);
+      derived d1 (d);
+      d1.sn++;
+      d1.s.change ();
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->update (d1);
+
+        assert (!d1.s.changed ());
+        assert (d.v != d1.v);
+
+        try
+        {
+          db->load (*pd, pd->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pd);
+          assert (!pd->s.loaded ());
+          db->load (*pd, pd->s);
+          assert (pd->sn == d1.sn);
+        }
+
+        db->reload (d);
+        assert (d.v == d1.v);
+        assert (d.sn == d1.sn);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      d1.sn++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->update (b1, b1.s); // No-op.
+        db->update (d1, d1.s);
+
+        assert (b.v == b1.v);
+        assert (d.v != d1.v);
+
+        try
+        {
+          db->load (*pd, pd->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pd);
+          assert (!pd->s.loaded ());
+          db->load (*pd, pd->s);
+
+          assert (pd->sn == d1.sn);
+        }
+
+        db->reload (d);
+        assert (d.v == d1.v);
+        assert (d.sn == d1.sn);
+        t.commit ();
+      }
+
+      // Update changed section.
+      //
+      d1.sn++;
+
+      {
+        transaction t (db->begin ());
+        db->update (d1, d1.s);
+
+        try
+        {
+          db->update (d, d.s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (d);
+          db->update (d, d.s);
+        }
+
+        t.commit ();
+      }
+    }
+
+    // Test reuse/polymorphic inheritance and optimistic mix.
+    //
+    {
+      using namespace test8;
+
+      derived d (123);
+
+      {
+        transaction t (db->begin ());
+        db->persist (d);
+        t.commit ();
+
+        assert (d.s.loaded ());
+      }
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        assert (!pd->s.loaded ());
+        assert (pd->sn != d.sn);
+
+        db->load (*pd, pd->s);
+
+        assert (pd->s.loaded ());
+        assert (pd->sn == d.sn);
+
+        t.commit ();
+      }
+
+      // Update object.
+      //
+      derived d1 (d);
+      d1.sn++;
+      d1.s.change ();
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->update (d1);
+
+        assert (!d1.s.changed ());
+        assert (d.v != d1.v);
+
+        try
+        {
+          db->load (*pd, pd->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pd);
+          assert (!pd->s.loaded ());
+          db->load (*pd, pd->s);
+          assert (pd->sn == d1.sn);
+        }
+
+        db->reload (d);
+        assert (d.v == d1.v);
+        assert (d.sn == d1.sn);
+        t.commit ();
+      }
+
+      // Update section.
+      //
+      d1.sn++;
+
+      {
+        transaction t (db->begin ());
+        auto_ptr<derived> pd (db->load<derived> (d.id));
+
+        db->update (d1, d1.s);
+        assert (d.v != d1.v);
+
+        try
+        {
+          db->load (*pd, pd->s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (*pd);
+          assert (!pd->s.loaded ());
+          db->load (*pd, pd->s);
+
+          assert (pd->sn == d1.sn);
+        }
+
+        db->reload (d);
+        assert (d.v == d1.v);
+        assert (d.sn == d1.sn);
+        t.commit ();
+      }
+
+      // Update changed section.
+      //
+      d1.sn++;
+
+      {
+        transaction t (db->begin ());
+        db->update (d1, d1.s);
+
+        try
+        {
+          db->update (d, d.s);
+          assert (false);
+        }
+        catch (const object_changed&)
+        {
+          db->reload (d);
+          db->update (d, d.s);
+        }
+
+        t.commit ();
+      }
+    }
+  }
+  catch (const odb::exception& e)
+  {
+    cerr << e.what () << endl;
+    return 1;
+  }
+}
diff --git a/common/section/polymorphism/makefile b/common/section/polymorphism/makefile
new file mode 100644
index 0000000..deb13dc
--- /dev/null
+++ b/common/section/polymorphism/makefile
@@ -0,0 +1,115 @@
+# file      : common/section/polymorphism/makefile
+# copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC
+# license   : GNU GPL v2; see accompanying LICENSE file
+
+include $(dir $(lastword $(MAKEFILE_LIST)))../../../build/bootstrap.make
+
+cxx_tun := driver.cxx
+odb_hdr := test.hxx
+genf    := $(call odb-gen,$(odb_hdr))
+gen     := $(addprefix $(out_base)/,$(genf))
+cxx_obj := $(addprefix $(out_base)/,$(cxx_tun:.cxx=.o)) $(filter %.o,$(gen:.cxx=.o))
+cxx_od  := $(cxx_obj:.o=.o.d)
+
+common.l             := $(out_root)/libcommon/common/common.l
+common.l.cpp-options := $(out_root)/libcommon/common/common.l.cpp-options
+
+# Import.
+#
+$(call import,\
+  $(scf_root)/import/odb/stub.make,\
+  odb: odb,odb-rules: odb_rules)
+
+# Build.
+#
+$(driver): $(cxx_obj) $(common.l)
+$(cxx_obj) $(cxx_od): cpp_options := -I$(out_base) -I$(src_base)
+$(cxx_obj) $(cxx_od): $(common.l.cpp-options)
+
+$(gen): $(odb)
+$(gen): odb := $(odb)
+$(gen) $(dist): export odb_options += --generate-schema --generate-query \
+--table-prefix t_section_p_
+$(gen): cpp_options := -I$(src_base)
+$(gen): $(common.l.cpp-options)
+
+ifneq ($(db_id),common)
+$(gen): odb_options += --database $(db_id)
+else
+$(gen): odb_options += --multi-database dynamic
+endif
+
+$(call include-dep,$(cxx_od),$(cxx_obj),$(gen))
+
+# Alias for default target.
+#
+$(out_base)/: $(driver)
+
+# Dist
+#
+name := $(subst /,-,$(subst $(src_root)/common/,,$(src_base)))
+
+$(dist): sources := $(cxx_tun)
+$(dist): headers := $(odb_hdr)
+$(dist): data_dist := test.std
+$(dist): export name := $(name)
+$(dist): export extra_dist := $(data_dist) $(call vc8projs,$(name)) \
+$(call vc9projs,$(name)) $(call vc10projs,$(name)) $(call vc11projs,$(name))
+$(dist):
+	$(call dist-data,$(sources) $(headers) $(data_dist))
+	$(call meta-automake,../../template/Makefile.am)
+	$(call meta-vc8projs,../../template/template,$(name))
+	$(call meta-vc9projs,../../template/template,$(name))
+	$(call meta-vc10projs,../../template/template,$(name))
+	$(call meta-vc11projs,../../template/template,$(name))
+
+# Test.
+#
+ifneq ($(db_id),common)
+$(eval $(call test-rule))
+else
+$(foreach d,$(databases),$(eval $(call test-rule,$d)))
+endif
+
+# Clean.
+#
+$(clean):                            \
+  $(driver).o.clean                  \
+  $(addsuffix .cxx.clean,$(cxx_obj)) \
+  $(addsuffix .cxx.clean,$(cxx_od))  \
+  $(addsuffix .hxx.clean,$(filter %.cxx,$(gen)))
+	$(call message,,rm -f $(out_base)/test.out)
+
+# Generated .gitignore.
+#
+ifeq ($(out_base),$(src_base))
+$(driver): | $(out_base)/.gitignore
+
+$(out_base)/.gitignore: files := driver $(genf)
+$(clean): $(out_base)/.gitignore.clean
+
+$(call include,$(bld_root)/git/gitignore.make)
+endif
+
+# How to.
+#
+$(call include,$(bld_root)/dist.make)
+$(call include,$(bld_root)/meta/vc8proj.make)
+$(call include,$(bld_root)/meta/vc9proj.make)
+$(call include,$(bld_root)/meta/vc10proj.make)
+$(call include,$(bld_root)/meta/vc11proj.make)
+$(call include,$(bld_root)/meta/automake.make)
+
+$(call include,$(bld_root)/cxx/standard.make) # cxx_standard
+ifdef cxx_standard
+$(gen): odb_options += --std $(cxx_standard)
+$(call include,$(odb_rules))
+endif
+
+$(call include,$(bld_root)/cxx/cxx-d.make)
+$(call include,$(bld_root)/cxx/cxx-o.make)
+$(call include,$(bld_root)/cxx/o-e.make)
+
+# Dependencies.
+#
+$(call import,$(src_root)/libcommon/makefile)
diff --git a/common/section/polymorphism/test.hxx b/common/section/polymorphism/test.hxx
new file mode 100644
index 0000000..f2081c2
--- /dev/null
+++ b/common/section/polymorphism/test.hxx
@@ -0,0 +1,495 @@
+// file      : common/section/polymorphism/test.hxx
+// copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef TEST_HXX
+#define TEST_HXX
+
+#include <string>
+#include <vector>
+
+#include <odb/core.hxx>
+#include <odb/section.hxx>
+
+// Test basic polymorphic section functionality.
+//
+#pragma db namespace table("t1_")
+namespace test1
+{
+  #pragma db object polymorphic abstract
+  struct root
+  {
+    root (int n): rs1n (n), rs2n (n), rs4n (n) {rs2v.push_back (n);}
+    virtual ~root () {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    // rs1: override in base and derived
+    //
+    #pragma db load(lazy) update(change)
+    odb::section rs1;
+
+    #pragma db section(rs1)
+    int rs1n;
+
+    // rs2: no override
+    //
+    #pragma db load(lazy)
+    odb::section rs2;
+
+    #pragma db section(rs2)
+    int rs2n;
+
+    #pragma db section(rs2)
+    std::vector<int> rs2v;
+
+    // rs3: empty
+    //
+    #pragma db load(lazy)
+    odb::section rs3;
+
+    // rs4: override "gap"
+    //
+    #pragma db load(lazy)
+    odb::section rs4;
+
+    #pragma db section(rs4)
+    int rs4n;
+  };
+
+  #pragma db object
+  struct base: root
+  {
+    base (int n = 999, const std::string& s = "xxx")
+        : root (n), rs1s (s), bs1n (n) {rs3v.push_back (n);}
+
+    // rs1
+    //
+    #pragma db section(rs1)
+    std::string rs1s;
+
+    // rs3
+    //
+    #pragma db section(rs3)
+    std::vector<int> rs3v;
+
+    // bs1: override in derived
+    //
+    #pragma db load(lazy)
+    odb::section bs1;
+
+    #pragma db section(bs1)
+    int bs1n;
+  };
+
+  #pragma db object
+  struct derived: base
+  {
+    derived (int n = 999, const std::string& s = "xxx", bool b = false)
+        : base (n, s), rs1b (b), rs3n (n), rs4s (s), bs1s (s), ds1n (n)
+    {rs1v.push_back (n);}
+
+    // rs1
+    //
+    #pragma db section(rs1)
+    bool rs1b;
+
+    #pragma db section(rs1)
+    std::vector<int> rs1v;
+
+    // rs3
+    //
+    #pragma db section(rs3)
+    int rs3n;
+
+    // rs4
+    //
+    #pragma db section(rs4)
+    std::string rs4s;
+
+    // bs1
+    //
+    #pragma db section(bs1)
+    std::string bs1s;
+
+    // ds1: no override
+    //
+    #pragma db load(lazy)
+    odb::section ds1;
+
+    #pragma db section(ds1)
+    int ds1n;
+  };
+}
+
+// Test empty section and override "gap".
+//
+#pragma db namespace table("t2_")
+namespace test2
+{
+  #pragma db object polymorphic abstract
+  struct root
+  {
+    virtual ~root () {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db load(lazy)
+    odb::section s;
+  };
+
+  #pragma db object abstract
+  struct base: root
+  {
+    // The "gap".
+  };
+
+  #pragma db object
+  struct derived: base
+  {
+    derived (int n = 999): sn (n) {sv.push_back (n);}
+
+    #pragma db section(s)
+    int sn;
+
+    #pragma db section(s)
+    std::vector<int> sv;
+  };
+}
+
+// Test value-only/container-only base/override combinations.
+//
+#pragma db namespace table("t3_")
+namespace test3
+{
+  #pragma db object polymorphic
+  struct root
+  {
+    root (int n = 999)
+        : s1n (n), s2n (n) {s3v.push_back (n); s4nv.push_back (n);}
+    virtual ~root () {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    // value/value
+    //
+    #pragma db load(lazy)
+    odb::section s1;
+
+    #pragma db section(s1)
+    int s1n;
+
+    // value/container
+    //
+    #pragma db load(lazy)
+    odb::section s2;
+
+    #pragma db section(s2)
+    int s2n;
+
+    // container/value
+    //
+    #pragma db load(lazy)
+    odb::section s3;
+
+    #pragma db section(s3)
+    std::vector<int> s3v;
+
+    // container/container
+    //
+    #pragma db load(lazy)
+    odb::section s4;
+
+    #pragma db section(s4)
+    std::vector<int> s4nv;
+  };
+
+  #pragma db object
+  struct base: root
+  {
+    base (int n = 999): root (n) {}
+
+    // The "gap".
+  };
+
+  #pragma db object
+  struct derived: base
+  {
+    derived (int n = 999, const std::string& s = "xxx")
+        : base (n), s1s (s), s3n (n) {s2v.push_back (n); s4sv.push_back (s);}
+
+    #pragma db section(s1)
+    std::string s1s;
+
+    #pragma db section(s2)
+    std::vector<int> s2v;
+
+    #pragma db section(s3)
+    int s3n;
+
+    #pragma db section(s4)
+    std::vector<std::string> s4sv;
+  };
+}
+
+// Test basic polymorphic optimistic section functionality.
+//
+#pragma db namespace table("t4_")
+namespace test4
+{
+  #pragma db object polymorphic optimistic abstract sectionable
+  struct root
+  {
+    root (int n): rs1n (n), rs2n (n), rs3n (n), rs4n (n) {}
+    virtual ~root () {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db version
+    unsigned long long v;
+
+    // rs1: readwrite, override
+    //
+    #pragma db load(lazy) update(change)
+    odb::section rs1;
+
+    #pragma db section(rs1)
+    int rs1n;
+
+    // rs2: readonly, no override
+    //
+    #pragma db load(lazy)
+    odb::section rs2;
+
+    #pragma db section(rs2)
+    const int rs2n;
+
+    // rs3: readonly, readonly override
+    //
+    #pragma db load(lazy)
+    odb::section rs3;
+
+    #pragma db section(rs3)
+    const int rs3n;
+
+    // rs4: readonly, readwrite override
+    //
+    #pragma db load(lazy)
+    odb::section rs4;
+
+    #pragma db section(rs4)
+    const int rs4n;
+  };
+
+  #pragma db object
+  struct base: root
+  {
+    base (int n = 999, const std::string& s = "xxx")
+        : root (n), rs1s (s), rs4s (s) {}
+
+    // rs1
+    //
+    #pragma db section(rs1)
+    std::string rs1s;
+
+    // rs4
+    //
+    #pragma db section(rs4)
+    std::string rs4s;
+
+    // bs2: empty, readwrite override
+    //
+    #pragma db load(lazy)
+    odb::section bs1;
+  };
+
+  #pragma db object
+  struct derived: base
+  {
+    derived (int n = 999, const std::string& s = "xxx", bool b = false)
+        : base (n, s), rs1b (b), rs3s (s), bs1n (n)
+    {
+      rs1v.push_back (n);
+      rs4v.push_back (n);
+      ds1v.push_back (n);
+    }
+
+    // rs1
+    //
+    #pragma db section(rs1)
+    bool rs1b;
+
+    #pragma db section(rs1)
+    std::vector<int> rs1v;
+
+    // rs3
+    //
+    #pragma db section(rs3)
+    const std::string rs3s;
+
+    // rs4
+    //
+    #pragma db section(rs4)
+    std::vector<int> rs4v;
+
+    // bs1
+    //
+    #pragma db section(bs1)
+    int bs1n;
+
+    // ds1: readwrite
+    //
+    #pragma db load(lazy)
+    odb::section ds1;
+
+    #pragma db section(ds1)
+    std::vector<int> ds1v;
+  };
+}
+
+// Test polymorphic optimistic readonly/empty to readwrite section override.
+//
+#pragma db namespace table("t5_")
+namespace test5
+{
+  #pragma db object polymorphic optimistic abstract
+  struct root
+  {
+    virtual ~root () {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db version
+    unsigned long long v;
+
+    #pragma db load(lazy) update(change)
+    odb::section s;
+  };
+
+  #pragma db object
+  struct base: root
+  {
+    // The "gap".
+  };
+
+  #pragma db object
+  struct derived: base
+  {
+    derived (int n = 999): sn (n) {}
+
+    #pragma db section(s)
+    int sn;
+  };
+}
+
+// Test polymorphic optimistic readonly/empty to readwrite section override,
+// eager-loaded case.
+//
+#pragma db namespace table("t6_")
+namespace test6
+{
+  #pragma db object polymorphic optimistic abstract
+  struct root
+  {
+    virtual ~root () {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db version
+    unsigned long long v;
+
+    #pragma db update(change)
+    odb::section s;
+  };
+
+  #pragma db object abstract
+  struct base: root
+  {
+    // The "gap".
+  };
+
+  #pragma db object
+  struct derived: base
+  {
+    derived (int n = 999): sn (n) {}
+
+    #pragma db section(s)
+    int sn;
+  };
+}
+
+// Test polymorphic optimistic section added in derived.
+//
+#pragma db namespace table("t7_")
+namespace test7
+{
+  #pragma db object polymorphic optimistic sectionable
+  struct root
+  {
+    virtual ~root () {}
+
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db version
+    unsigned long long v;
+  };
+
+  #pragma db object
+  struct base: root
+  {
+    #pragma db load(lazy) update(change)
+    odb::section s;
+  };
+
+  #pragma db object
+  struct derived: base
+  {
+    derived (int n = 999): sn (n) {}
+
+    #pragma db section(s)
+    int sn;
+  };
+}
+
+// Test reuse/polymorphic inheritance and optimistic mix.
+//
+#pragma db namespace table("t8_")
+namespace test8
+{
+  #pragma db object optimistic sectionable abstract
+  struct root
+  {
+    #pragma db id auto
+    unsigned long id;
+
+    #pragma db version
+    unsigned long long v;
+  };
+
+  #pragma db object polymorphic sectionable
+  struct base: root
+  {
+    virtual ~base () {}
+  };
+
+  #pragma db object
+  struct derived: base
+  {
+    derived (int n = 999): sn (n) {}
+
+    #pragma db load(lazy) update(change)
+    odb::section s;
+
+    #pragma db section(s)
+    int sn;
+  };
+}
+
+#endif // TEST_HXX
diff --git a/common/section/polymorphism/test.std b/common/section/polymorphism/test.std
new file mode 100644
index 0000000..e69de29
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