New design for NULL semantics

Now, instead of being specified as part of the SQL type with the type
pragma, there are separate null and not_null pragmas. The not_null
pragma was used to control NULL-ness of object pointers. Now the two
pragmas are used consistently for object pointers and simple values
(and in the future will work for composite values and containers).

4 files changed, 22 insertions, 15 deletions

diff --git a/odb/relational/mysql/context.cxx b/odb/relational/mysql/context.cxx
index e9446c2..431470a 100644
--- a/odb/relational/mysql/context.cxx
+++ b/odb/relational/mysql/context.cxx
@@ -234,12 +234,9 @@ namespace relational
     }
 
     string context::
-    database_type_impl (semantics::type& t,
-                        semantics::names* hint,
-                        semantics::context& ctx,
-                        column_type_flags f)
+    database_type_impl (semantics::type& t, semantics::names* hint, bool id)
     {
-      string r (base_context::database_type_impl (t, hint, ctx, f));
+      string r (base_context::database_type_impl (t, hint, id));
 
       if (!r.empty ())
         return r;
@@ -290,9 +287,6 @@ namespace relational
           if (e->unsigned_ ())
             r += " UNSIGNED";
         }
-
-        if ((f & ctf_default_null) == 0)
-          r += " NOT NULL";
       }
 
       return r;
diff --git a/odb/relational/mysql/context.hxx b/odb/relational/mysql/context.hxx
index 019b878..00ebe57 100644
--- a/odb/relational/mysql/context.hxx
+++ b/odb/relational/mysql/context.hxx
@@ -97,10 +97,7 @@ namespace relational
 
     protected:
       virtual string
-      database_type_impl (semantics::type&,
-                          semantics::names*,
-                          semantics::context&,
-                          column_type_flags);
+      database_type_impl (semantics::type&, semantics::names*, bool);
 
     public:
       virtual
diff --git a/odb/relational/mysql/schema.cxx b/odb/relational/mysql/schema.cxx
index 0b44c53..3848c75 100644
--- a/odb/relational/mysql/schema.cxx
+++ b/odb/relational/mysql/schema.cxx
@@ -37,11 +37,27 @@ namespace relational
         }
       };
 
-      struct object_columns: relational::object_columns
+      struct object_columns: relational::object_columns, context
       {
         object_columns (base const& x): base (x) {}
 
         virtual void
+        null (semantics::data_member& m)
+        {
+          if (!context::null (m, prefix_))
+            os << " NOT NULL";
+          else
+          {
+            // 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 (column_sql_type (m, prefix_).type == sql_type::TIMESTAMP)
+              os << " NULL";
+          }
+        }
+
+        virtual void
         constraints (semantics::data_member& m)
         {
           base::constraints (m);
diff --git a/odb/relational/mysql/source.cxx b/odb/relational/mysql/source.cxx
index 17bffdc..d3b4129 100644
--- a/odb/relational/mysql/source.cxx
+++ b/odb/relational/mysql/source.cxx
@@ -588,7 +588,7 @@ namespace relational
             {
               os << "}";
 
-              if (!null_pointer (mi.m, key_prefix_))
+              if (!null (mi.m, key_prefix_))
                 os << "else" << endl
                    << "throw null_pointer ();";
             }
@@ -786,7 +786,7 @@ namespace relational
                  << endl
                  << "if (i." << mi.var << "null)" << endl;
 
-              if (null_pointer (mi.m, key_prefix_))
+              if (null (mi.m, key_prefix_))
                 os << member << " = ptr_traits::pointer_type ();";
               else
                 os << "throw null_pointer ();";