Don't override NOT NULL on Oracle VARCHAR column if it's primary key

2 files changed, 27 insertions, 7 deletions

diff --git a/doc/manual.xhtml b/doc/manual.xhtml
index 6257cf7..e14f2cf 100644
--- a/doc/manual.xhtml
+++ b/doc/manual.xhtml
@@ -13261,10 +13261,13 @@ SHOW integer_datetimes
 
   <p>In Oracle empty <code>VARCHAR2</code> and <code>NVARCHAR2</code>
      strings are represented as <code>NULL</code> values. As a result,
-     in the generated schema, columns of these types are always
-     declared as <code>NULL</code>, even if explicitly declared as
+     in the generated schema, columns of these types are declared as
+     <code>NULL</code> even if explicitly declared as
      <code>NOT NULL</code> with the <code>db&nbsp;not_null</code> pragma
-     (<a href="#12.4.5">Section 12.4.5, "<code>null/not_null</code>"</a>).</p>
+     (<a href="#12.4.5">Section 12.4.5, "<code>null/not_null</code>"</a>),
+     except for primary key columns. This also means that for object ids
+     that are mapped to these Oracle types, an empty string is an invalid
+     value.</p>
 
   <p>The Oracle ODB runtime library also provides support for mapping the
      <code>std::string</code> type to the Oracle <code>CHAR</code>,
diff --git a/odb/relational/oracle/schema.cxx b/odb/relational/oracle/schema.cxx
index 2fd0602..2835520 100644
--- a/odb/relational/oracle/schema.cxx
+++ b/odb/relational/oracle/schema.cxx
@@ -153,9 +153,9 @@ namespace relational
         null (sema_rel::column& c)
         {
           // Oracle interprets empty VARCHAR2 and NVARCHAR2 strings as
-          // NULL. As an empty string is always valid within the C++
-          // context, VARCHAR2 and NVARCHAR2 columns are always
-          // specified as nullable.
+          // NULL. As an empty string is valid within the C++ context,
+          // VARCHAR2 and NVARCHAR2 columns are always specified as
+          // nullable, except when are a part of a primary key.
           //
           if (!c.null ())
           {
@@ -164,7 +164,24 @@ namespace relational
             sql_type const& t (parse_sql_type (c.type ()));
 
             if (t.type == sql_type::VARCHAR2 || t.type == sql_type::NVARCHAR2)
-              return;
+            {
+              // See if this column is a part of a primary key.
+              //
+              bool pk (false);
+
+              for (sema_rel::column::contained_iterator i (
+                     c.contained_begin ()); i != c.contained_end (); ++i)
+              {
+                if (i->key ().is_a<sema_rel::primary_key> ())
+                {
+                  pk = true;
+                  break;
+                }
+              }
+
+              if (!pk)
+                return;
+            }
           }
 
           base::null (c);