From 17e48b8980d89f0c5c3a00d4066c764093838e5a Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 5 Apr 2013 10:51:03 +0200
Subject: Explicitly specify NULL for nullable columns in generated schema

---
 NEWS                            |  3 +++
 odb/relational/mysql/schema.cxx | 23 -----------------------
 odb/relational/schema.hxx       |  6 ++++--
 3 files changed, 7 insertions(+), 25 deletions(-)

diff --git a/NEWS b/NEWS
index a7cad45..c6b2db3 100644
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,9 @@ Version 2.3.0
  * The --output-name option has been renamed to --input-name, which is more
    semantically correct.
 
+ * The generated database schemas now explicitly specify NULL for nullable
+   columns.
+
 Version 2.2.0
 
  * Multi-database support. This mechanism allows an application to
diff --git a/odb/relational/mysql/schema.cxx b/odb/relational/mysql/schema.cxx
index 6ce619b..2ae47ae 100644
--- a/odb/relational/mysql/schema.cxx
+++ b/odb/relational/mysql/schema.cxx
@@ -143,29 +143,6 @@ namespace relational
         create_column (base const& x): base (x) {}
 
         virtual void
-        null (sema_rel::column& c)
-        {
-          // MySQL TIMESTAMP is by default NOT NULL. If we want it
-          // to contain NULL values, we need to explicitly declare
-          // the column as NULL.
-          //
-          if (c.null ())
-          {
-            // This should never fail since we have already parsed this.
-            //
-            sql_type const& t (parse_sql_type (c.type ()));
-
-            if (t.type == sql_type::TIMESTAMP)
-            {
-              os << " NULL";
-              return;
-            }
-          }
-
-          base::null (c);
-        }
-
-        virtual void
         auto_ (sema_rel::column&)
         {
           os << " AUTO_INCREMENT";
diff --git a/odb/relational/schema.hxx b/odb/relational/schema.hxx
index 69e8089..fcb176f 100644
--- a/odb/relational/schema.hxx
+++ b/odb/relational/schema.hxx
@@ -410,8 +410,10 @@ namespace relational
       virtual void
       null (sema_rel::column& c)
       {
-        if (!c.null ())
-          os << " NOT NULL";
+        // Specify both cases explicitly for better readability,
+        // especially in ALTER COLUMN clauses.
+        //
+        os << (c.null () ? " NULL" : " NOT NULL");
       }
 
       virtual void
-- 
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