Add support for unidirectional object relationships

New test: common/relationship.

7 files changed, 393 insertions, 247 deletions

diff --git a/odb/mysql/common.cxx b/odb/mysql/common.cxx
index 17cae9e..d7e6187 100644
--- a/odb/mysql/common.cxx
+++ b/odb/mysql/common.cxx
@@ -33,130 +33,149 @@ namespace mysql
 
     semantics::type& t (type_override_ != 0 ? *type_override_ : m.type ());
 
-    member_info mi (m, t, var, fq_type_override_);
-
     if (comp_value (t))
     {
+      member_info mi (m, t, var, fq_type_override_);
       pre (mi);
       traverse_composite (mi);
+      post (mi);
     }
     else if (container (t))
     {
+      member_info mi (m, t, var, fq_type_override_);
       pre (mi);
       traverse_container (mi);
+      post (mi);
     }
     else
     {
       sql_type const& st (db_type (m, key_prefix_));
-      mi.st = &st;
-      pre (mi);
 
-      switch (st.type)
+      if (semantics::class_* c = object_pointer (m, key_prefix_))
       {
-        // Integral types.
-        //
-      case sql_type::TINYINT:
-      case sql_type::SMALLINT:
-      case sql_type::MEDIUMINT:
-      case sql_type::INT:
-      case sql_type::BIGINT:
-        {
-          traverse_integer (mi);
-          break;
-        }
-
-        // Float types.
-        //
-      case sql_type::FLOAT:
-      case sql_type::DOUBLE:
-        {
-          traverse_float (mi);
-          break;
-        }
-      case sql_type::DECIMAL:
-        {
-          traverse_decimal (mi);
-          break;
-        }
-
-        // Data-time types.
+        member_info mi (m, id_member (*c).type (), var, fq_type_override_);
+        mi.st = &st;
+        pre (mi);
+        traverse_object_pointer (mi);
+        post (mi);
+      }
+      else
+      {
+        member_info mi (m, t, var, fq_type_override_);
+        mi.st = &st;
+        pre (mi);
+        traverse_simple (mi);
+        post (mi);
+      }
+    }
+  }
+
+  void member_base::
+  traverse_simple (member_info& mi)
+  {
+    switch (mi.st->type)
+    {
+      // Integral types.
+      //
+    case sql_type::TINYINT:
+    case sql_type::SMALLINT:
+    case sql_type::MEDIUMINT:
+    case sql_type::INT:
+    case sql_type::BIGINT:
+      {
+        traverse_integer (mi);
+        break;
+      }
+
+      // Float types.
+      //
+    case sql_type::FLOAT:
+    case sql_type::DOUBLE:
+      {
+        traverse_float (mi);
+        break;
+      }
+    case sql_type::DECIMAL:
+      {
+        traverse_decimal (mi);
+        break;
+      }
+
+      // Data-time types.
+      //
+    case sql_type::DATE:
+    case sql_type::TIME:
+    case sql_type::DATETIME:
+    case sql_type::TIMESTAMP:
+    case sql_type::YEAR:
+      {
+        traverse_date_time (mi);
+        break;
+      }
+
+      // String and binary types.
+      //
+    case sql_type::CHAR:
+    case sql_type::VARCHAR:
+    case sql_type::TINYTEXT:
+    case sql_type::TEXT:
+    case sql_type::MEDIUMTEXT:
+    case sql_type::LONGTEXT:
+      {
+        // For string types the limit is in characters rather
+        // than in bytes. The fixed-length pre-allocated buffer
+        // optimization can only be used for 1-byte encodings.
+        // To support this we will need the character encoding
+        // in sql_type.
         //
-      case sql_type::DATE:
-      case sql_type::TIME:
-      case sql_type::DATETIME:
-      case sql_type::TIMESTAMP:
-      case sql_type::YEAR:
-        {
-          traverse_date_time (mi);
-          break;
-        }
-
-        // String and binary types.
+        traverse_long_string (mi);
+        break;
+      }
+    case sql_type::BINARY:
+    case sql_type::TINYBLOB:
+      {
+        // BINARY's range is always 255 or less from MySQL 5.0.3.
+        // TINYBLOB can only store up to 255 bytes.
         //
-      case sql_type::CHAR:
-      case sql_type::VARCHAR:
-      case sql_type::TINYTEXT:
-      case sql_type::TEXT:
-      case sql_type::MEDIUMTEXT:
-      case sql_type::LONGTEXT:
-        {
-          // For string types the limit is in characters rather
-          // than in bytes. The fixed-length pre-allocated buffer
-          // optimization can only be used for 1-byte encodings.
-          // To support this we will need the character encoding
-          // in sql_type.
-          //
-          traverse_long_string (mi);
-          break;
-        }
-      case sql_type::BINARY:
-      case sql_type::TINYBLOB:
-        {
-          // BINARY's range is always 255 or less from MySQL 5.0.3.
-          // TINYBLOB can only store up to 255 bytes.
-          //
+        traverse_short_string (mi);
+        break;
+      }
+    case sql_type::VARBINARY:
+    case sql_type::BLOB:
+    case sql_type::MEDIUMBLOB:
+    case sql_type::LONGBLOB:
+      {
+        if (mi.st->range && mi.st->range_value <= 255)
           traverse_short_string (mi);
-          break;
-        }
-      case sql_type::VARBINARY:
-      case sql_type::BLOB:
-      case sql_type::MEDIUMBLOB:
-      case sql_type::LONGBLOB:
-        {
-          if (st.range && st.range_value <= 255)
-            traverse_short_string (mi);
-          else
-            traverse_long_string (mi);
-
-          break;
-        }
-
-        // Other types.
-        //
-      case sql_type::BIT:
-        {
-          traverse_bit (mi);
-          break;
-        }
-      case sql_type::ENUM:
-        {
-          traverse_enum (mi);
-          break;
-        }
-      case sql_type::SET:
-        {
-          traverse_set (mi);
-          break;
-        }
-      case sql_type::invalid:
-        {
-          assert (false);
-          break;
-        }
+        else
+          traverse_long_string (mi);
+
+        break;
       }
-    }
 
-    post (mi);
+      // Other types.
+      //
+    case sql_type::BIT:
+      {
+        traverse_bit (mi);
+        break;
+      }
+    case sql_type::ENUM:
+      {
+        traverse_enum (mi);
+        break;
+      }
+    case sql_type::SET:
+      {
+        traverse_set (mi);
+        break;
+      }
+    case sql_type::invalid:
+      {
+        assert (false);
+        break;
+      }
+    }
   }
 
   //
diff --git a/odb/mysql/common.hxx b/odb/mysql/common.hxx
index 31c6962..fb1f2a3 100644
--- a/odb/mysql/common.hxx
+++ b/odb/mysql/common.hxx
@@ -46,7 +46,13 @@ namespace mysql
       string
       fq_type () const
       {
-        return fq_type_.empty () ? t.fq_name (m.belongs ().hint ()) : fq_type_;
+        // Use the original type from 'm' instead of 't' since the hint
+        // may be invalid for a different type. Plus, if a type is
+        // overriden, then the fq_type must be as well.
+        //
+        return fq_type_.empty ()
+          ? m.type ().fq_name (m.belongs ().hint ())
+          : fq_type_;
       }
 
       string const& fq_type_;
@@ -81,6 +87,15 @@ namespace mysql
     }
 
     virtual void
+    traverse_object_pointer (member_info& mi)
+    {
+      traverse_simple (mi);
+    }
+
+    virtual void
+    traverse_simple (member_info&);
+
+    virtual void
     traverse_integer (member_info&)
     {
     }
diff --git a/odb/mysql/context.cxx b/odb/mysql/context.cxx
index 4803da2..de3eed0 100644
--- a/odb/mysql/context.cxx
+++ b/odb/mysql/context.cxx
@@ -26,28 +26,28 @@ namespace mysql
 
     type_map_entry type_map[] =
     {
-      {"bool", "TINYINT(1) NOT NULL", 0},
+      {"bool", "TINYINT(1)", 0},
 
-      {"char", "TINYINT NOT NULL", 0},
-      {"signed char", "TINYINT NOT NULL", 0},
-      {"unsigned char", "TINYINT UNSIGNED NOT NULL", 0},
+      {"char", "TINYINT", 0},
+      {"signed char", "TINYINT", 0},
+      {"unsigned char", "TINYINT UNSIGNED", 0},
 
-      {"short int", "SMALLINT NOT NULL", 0},
-      {"short unsigned int", "SMALLINT UNSIGNED NOT NULL", 0},
+      {"short int", "SMALLINT", 0},
+      {"short unsigned int", "SMALLINT UNSIGNED", 0},
 
-      {"int", "INT NOT NULL", 0},
-      {"unsigned int", "INT UNSIGNED NOT NULL", 0},
+      {"int", "INT", 0},
+      {"unsigned int", "INT UNSIGNED", 0},
 
-      {"long int", "BIGINT NOT NULL", 0},
-      {"long unsigned int", "BIGINT UNSIGNED NOT NULL", 0},
+      {"long int", "BIGINT", 0},
+      {"long unsigned int", "BIGINT UNSIGNED", 0},
 
-      {"long long int", "BIGINT NOT NULL", 0},
-      {"long long unsigned int", "BIGINT UNSIGNED NOT NULL", 0},
+      {"long long int", "BIGINT", 0},
+      {"long long unsigned int", "BIGINT UNSIGNED", 0},
 
-      {"float", "FLOAT NOT NULL", 0},
-      {"double", "DOUBLE NOT NULL", 0},
+      {"float", "FLOAT", 0},
+      {"double", "DOUBLE", 0},
 
-      {"::std::string", "TEXT NOT NULL", "VARCHAR(255) NOT NULL"}
+      {"::std::string", "TEXT", "VARCHAR (255)"}
     };
   }
 
@@ -145,8 +145,10 @@ namespace mysql
       virtual void
       traverse_composite (member_info& mi)
       {
+        // Reset any overrides.
+        //
         if (!hg_.r_)
-          hg_.r_ = hg_.dispatch (dynamic_cast<semantics::class_&> (mi.t));
+          hg_.r_ = context::grow (dynamic_cast<semantics::class_&> (mi.t));
       }
 
       virtual void
@@ -216,11 +218,12 @@ namespace mysql
   string context::data::
   column_type_impl (semantics::type& t,
                     string const& type,
-                    semantics::context* ctx) const
+                    semantics::context& ctx,
+                    column_type_flags f) const
   {
-    string r (::context::data::column_type_impl (t, type, ctx));
+    string r (::context::data::column_type_impl (t, type, ctx, f));
 
-    if (!r.empty () && ctx != 0 && ctx->count ("auto"))
+    if (!r.empty () && ctx.count ("auto") && (f & ctf_object_id_ref) == 0)
       r += " AUTO_INCREMENT";
 
     return r;
diff --git a/odb/mysql/context.hxx b/odb/mysql/context.hxx
index 9a6beec..4ac36ca 100644
--- a/odb/mysql/context.hxx
+++ b/odb/mysql/context.hxx
@@ -105,7 +105,8 @@ namespace mysql
       virtual string
       column_type_impl (semantics::type&,
                         string const& type,
-                        semantics::context*) const;
+                        semantics::context&,
+                        column_type_flags) const;
     };
 
   private:
diff --git a/odb/mysql/header.cxx b/odb/mysql/header.cxx
index 79b8d67..130a2ba 100644
--- a/odb/mysql/header.cxx
+++ b/odb/mysql/header.cxx
@@ -525,24 +525,25 @@ namespace mysql
         {
         case ck_ordered:
           {
-            os << "init (index_type&, value_type&, const data_image_type&);";
+            os << "init (index_type&, value_type&, ";
             break;
           }
         case ck_map:
         case ck_multimap:
           {
-            os << "init (key_type&, value_type&, const data_image_type&);";
+            os << "init (key_type&, value_type&, ";
             break;
           }
         case ck_set:
         case ck_multiset:
           {
-            os << "init (value_type&, const data_image_type&);";
+            os << "init (value_type&, ";
             break;
           }
         }
 
-        os << endl;
+        os << "const data_image_type&, database&);"
+           << endl;
 
         // insert_one
         //
@@ -801,7 +802,7 @@ namespace mysql
         // init (object, image)
         //
         os << "static void" << endl
-           << "init (object_type&, const image_type&);"
+           << "init (object_type&, const image_type&, database&);"
            << endl;
 
         // persist ()
@@ -895,7 +896,7 @@ namespace mysql
         // init (object, image)
         //
         os << "static void" << endl
-           << "init (value_type&, const image_type&);"
+           << "init (value_type&, const image_type&, database&);"
            << endl;
 
         os << "};";
diff --git a/odb/mysql/schema.cxx b/odb/mysql/schema.cxx
index 1dfeb1f..0c004ad 100644
--- a/odb/mysql/schema.cxx
+++ b/odb/mysql/schema.cxx
@@ -18,8 +18,8 @@ namespace mysql
 
     struct object_columns: object_columns_base, context
     {
-      object_columns (context& c)
-          : object_columns_base (c), context (c)
+      object_columns (context& c, string const& prefix = string ())
+          : object_columns_base (c), context (c), prefix_ (prefix)
       {
       }
 
@@ -29,11 +29,21 @@ namespace mysql
         if (!first)
           os << "," << endl;
 
-        os << "  `" << name << "` " << column_type (m);
+        os << "  `" << name << "` " << column_type (m, prefix_);
 
         if (m.count ("id"))
           os << " PRIMARY KEY";
+
+        using semantics::class_;
+        if (class_* c = object_pointer (m, prefix_))
+        {
+          os << " REFERENCES `" << table_name (*c) << "` (`" <<
+            column_name (id_member (*c)) << "`)";
+        }
       }
+
+    private:
+      string prefix_;
     };
 
     struct member_create: object_members_base, context
@@ -67,7 +77,7 @@ namespace mysql
         // object_id (simple value)
         //
         string id_name (column_name (m, "id", "object_id"));
-        os << "  `" << id_name << "` " << column_type (id_member_);
+        os << "  `" << id_name << "` " << column_type (id_member_, "ref");
 
         // index (simple value)
         //
@@ -95,8 +105,9 @@ namespace mysql
           }
           else
           {
+            object_columns oc (*this, "key");
             string const& name (column_name (m, "key", "key"));
-            os << "  `" << name << "` " << column_type (m, "key");
+            oc.column (m, name, true);
           }
         }
 
@@ -112,8 +123,9 @@ namespace mysql
           }
           else
           {
+            object_columns oc (*this, "value");
             string const& name (column_name (m, "value", "value"));
-            os << "  `" << name << "` " << column_type (m, "value");
+            oc.column (m, name, true);
           }
         }
 
diff --git a/odb/mysql/source.cxx b/odb/mysql/source.cxx
index 2f65de6..8351ad5 100644
--- a/odb/mysql/source.cxx
+++ b/odb/mysql/source.cxx
@@ -516,19 +516,6 @@ namespace mysql
       {
         if (container (mi.t))
           return;
-        else if (comp_value (mi.t))
-          traits = "composite_value_traits< " + mi.fq_type () + " >";
-        else
-        {
-          type = mi.fq_type ();
-          image_type = member_image_type_.image_type (mi.m);
-          db_type = member_database_type_.database_type (mi.m);
-
-          traits = "mysql::value_traits< "
-            + type + ", "
-            + image_type + ", "
-            + db_type + " >";
-        }
 
         if (!member_override_.empty ())
           member = member_override_;
@@ -540,6 +527,65 @@ namespace mysql
           os << "// " << name << endl
              << "//" << endl;
         }
+
+        if (comp_value (mi.t))
+          traits = "composite_value_traits< " + mi.fq_type () + " >";
+        else
+        {
+          if (semantics::class_* c = object_pointer (mi.m, key_prefix_))
+          {
+            type = "obj_traits::id_type";
+            image_type = member_image_type_.image_type (mi.m);
+            db_type = member_database_type_.database_type (mi.m);
+
+            // Handle NULL pointers and extract the id.
+            //
+            os << "{"
+               << "typedef object_traits< " << c->fq_name () <<
+              " > obj_traits;"
+               << "typedef pointer_traits< " << mi.fq_type () <<
+              " > ptr_traits;"
+               << endl
+               << "bool is_null (ptr_traits::null_ptr (" << member << "));"
+               << "if (!is_null)"
+               << "{"
+               << "const " << type << "& id (" << endl
+               << "obj_traits::id (ptr_traits::get_ref (" << member << ")));"
+               << endl;
+
+            member = "id";
+          }
+          else
+          {
+            type = mi.fq_type ();
+            image_type = member_image_type_.image_type (mi.m);
+            db_type = member_database_type_.database_type (mi.m);
+
+            os << "{"
+               << "bool is_null;";
+          }
+
+          traits = "mysql::value_traits<\n    "
+            + type + ",\n    "
+            + image_type + ",\n    "
+            + db_type + " >";
+        }
+      }
+
+      virtual void
+      post (member_info& mi)
+      {
+        if (container (mi.t))
+          return;
+
+        if (!comp_value (mi.t))
+        {
+          if (object_pointer (mi.m, key_prefix_))
+            os << "}";
+
+          os << "i." << mi.var << "null = is_null;"
+             << "}";
+        }
       }
 
       virtual void
@@ -555,23 +601,15 @@ namespace mysql
       virtual void
       traverse_integer (member_info& mi)
       {
-        os << "{"
-           << "bool is_null;"
-           << traits << "::set_image (" << endl
-           << "i." << mi.var << "value, is_null, " << member << ");"
-           << "i." << mi.var << "null = is_null;"
-           << "}";
+        os << traits << "::set_image (" << endl
+           << "i." << mi.var << "value, is_null, " << member << ");";
       }
 
       virtual void
       traverse_float (member_info& mi)
       {
-        os << "{"
-           << "bool is_null;"
-           << traits << "::set_image (" << endl
-           << "i." << mi.var << "value, is_null, " << member << ");"
-           << "i." << mi.var << "null = is_null;"
-           << "}";
+        os << traits << "::set_image (" << endl
+           << "i." << mi.var << "value, is_null, " << member << ");";
       }
 
       virtual void
@@ -579,9 +617,7 @@ namespace mysql
       {
         // @@ Optimization: can remove growth check if buffer is fixed.
         //
-        os << "{"
-           << "bool is_null;"
-           << "std::size_t size;"
+        os << "std::size_t size;"
            << "std::size_t cap (i." << mi.var << "value.capacity ());"
            << traits << "::set_image (" << endl
            << "i." << mi.var << "value," << endl
@@ -589,20 +625,14 @@ namespace mysql
            << "is_null," << endl
            << member << ");"
            << "i." << mi.var << "size = static_cast<unsigned long> (size);"
-           << "i." << mi.var << "null = is_null;"
-           << "grew = grew || (cap != i." << mi.var << "value.capacity ());"
-           << "}";
+           << "grew = grew || (cap != i." << mi.var << "value.capacity ());";
       }
 
       virtual void
       traverse_date_time (member_info& mi)
       {
-        os << "{"
-           << "bool is_null;"
-           << traits << "::set_image (" << endl
-           << "i." << mi.var << "value, is_null, " << member << ");"
-           << "i." << mi.var << "null = is_null;"
-           << "}";
+        os << traits << "::set_image (" << endl
+           << "i." << mi.var << "value, is_null, " << member << ");";
       }
 
       virtual void
@@ -610,9 +640,7 @@ namespace mysql
       {
         // @@ Optimization: can remove growth check if buffer is fixed.
         //
-        os << "{"
-           << "bool is_null;"
-           << "std::size_t size;"
+        os << "std::size_t size;"
            << "std::size_t cap (i." << mi.var << "value.capacity ());"
            << traits << "::set_image (" << endl
            << "i." << mi.var << "value," << endl
@@ -620,17 +648,13 @@ namespace mysql
            << "is_null," << endl
            << member << ");"
            << "i." << mi.var << "size = static_cast<unsigned long> (size);"
-           << "i." << mi.var << "null = is_null;"
-           << "grew = grew || (cap != i." << mi.var << "value.capacity ());"
-           << "}";
+           << "grew = grew || (cap != i." << mi.var << "value.capacity ());";
       }
 
       virtual void
       traverse_long_string (member_info& mi)
       {
-        os << "{"
-           << "bool is_null;"
-           << "std::size_t size;"
+        os << "std::size_t size;"
            << "std::size_t cap (i." << mi.var << "value.capacity ());"
            << traits << "::set_image (" << endl
            << "i." << mi.var << "value," << endl
@@ -638,9 +662,7 @@ namespace mysql
            << "is_null," << endl
            << member << ");"
            << "i." << mi.var << "size = static_cast<unsigned long> (size);"
-           << "i." << mi.var << "null = is_null;"
-           << "grew = grew || (cap != i." << mi.var << "value.capacity ());"
-           << "}";
+           << "grew = grew || (cap != i." << mi.var << "value.capacity ());";
       }
 
       virtual void
@@ -648,18 +670,14 @@ namespace mysql
       {
         // Represented as a BLOB.
         //
-        os << "{"
-           << "bool is_null;"
-           << "std::size_t size;"
+        os << "std::size_t size;"
            << traits << "::set_image (" << endl
            << "i." << mi.var << "value," << endl
            << "sizeof (i." << mi.var << "value)," << endl
            << "size," << endl
            << "is_null," << endl
            << member << ");"
-           << "i." << mi.var << "size = static_cast<unsigned long> (size);"
-           << "i." << mi.var << "null = is_null;"
-           << "}";
+           << "i." << mi.var << "size = static_cast<unsigned long> (size);";
       }
 
       virtual void
@@ -667,9 +685,7 @@ namespace mysql
       {
         // Represented as a string.
         //
-        os << "{"
-           << "bool is_null;"
-           << "std::size_t size;"
+        os << "std::size_t size;"
            << "std::size_t cap (i." << mi.var << "value.capacity ());"
            << traits << "::set_image (" << endl
            << "i." << mi.var << "value," << endl
@@ -677,9 +693,7 @@ namespace mysql
            << "is_null," << endl
            << member << ");"
            << "i." << mi.var << "size = static_cast<unsigned long> (size);"
-           << "i." << mi.var << "null = is_null;"
-           << "grew = grew || (cap != i." << mi.var << "value.capacity ());"
-           << "}";
+           << "grew = grew || (cap != i." << mi.var << "value.capacity ());";
       }
 
       virtual void
@@ -687,9 +701,7 @@ namespace mysql
       {
         // Represented as a string.
         //
-        os << "{"
-           << "bool is_null;"
-           << "std::size_t size;"
+        os << "std::size_t size;"
            << "std::size_t cap (i." << mi.var << "value.capacity ());"
            << traits << "::set_image (" << endl
            << "i." << mi.var << "value," << endl
@@ -697,9 +709,7 @@ namespace mysql
            << "is_null," << endl
            << member << ");"
            << "i." << mi.var << "size = static_cast<unsigned long> (size);"
-           << "i." << mi.var << "null = is_null;"
-           << "grew = grew || (cap != i." << mi.var << "value.capacity ());"
-           << "}";
+           << "grew = grew || (cap != i." << mi.var << "value.capacity ());";
       }
 
     private:
@@ -766,19 +776,6 @@ namespace mysql
       {
         if (container (mi.t))
           return;
-        else if (comp_value (mi.t))
-          traits = "composite_value_traits< " + mi.fq_type () + " >";
-        else
-        {
-          type = mi.fq_type ();
-          image_type = member_image_type_.image_type (mi.m);
-          db_type = member_database_type_.database_type (mi.m);
-
-          traits = "mysql::value_traits< "
-            + type + ", "
-            + image_type + ", "
-            + db_type + " >";
-        }
 
         if (!member_override_.empty ())
           member = member_override_;
@@ -790,13 +787,75 @@ namespace mysql
           os << "// " << name << endl
              << "//" << endl;
         }
+
+        if (comp_value (mi.t))
+          traits = "composite_value_traits< " + mi.fq_type () + " >";
+        else
+        {
+          if (semantics::class_* c = object_pointer (mi.m, key_prefix_))
+          {
+            type = "obj_traits::id_type";
+            image_type = member_image_type_.image_type (mi.m);
+            db_type = member_database_type_.database_type (mi.m);
+
+            // Handle NULL pointers and extract the id.
+            //
+            os << "{"
+               << "typedef object_traits< " << c->fq_name () <<
+              " > obj_traits;"
+               << "typedef pointer_traits< " << mi.fq_type () <<
+              " > ptr_traits;"
+               << endl
+               << "if (i." << mi.var << "null)" << endl
+               << member << " = ptr_traits::pointer_type ();"
+               << "else"
+               << "{"
+               << type << " id;";
+
+            member = "id";
+          }
+          else
+          {
+            type = mi.fq_type ();
+            image_type = member_image_type_.image_type (mi.m);
+            db_type = member_database_type_.database_type (mi.m);
+          }
+
+          traits = "mysql::value_traits<\n    "
+            + type + ",\n    "
+            + image_type + ",\n    "
+            + db_type + " >";
+        }
+      }
+
+      virtual void
+      post (member_info& mi)
+      {
+        if (container (mi.t))
+          return;
+
+        if (!comp_value (mi.t) && object_pointer (mi.m, key_prefix_))
+        {
+          member = member_override_.empty ()
+            ? "o." + mi.m.name ()
+            : member_override_;
+
+          os << "// If a compiler error points to the line below, then" << endl
+             << "// it most likely means that a pointer used in a member" << endl
+             << "// cannot be initialized from an object pointer." << endl
+             << "//" << endl
+             << member << " = ptr_traits::pointer_type (" << endl
+             << "db.load< obj_traits::object_type > (id));"
+             << "}"
+             << "}";
+        }
       }
 
       virtual void
       traverse_composite (member_info& mi)
       {
         os << traits << "::init (" << member << ", i." <<
-          mi.var << "value);"
+          mi.var << "value, db);"
            << endl;
       }
 
@@ -924,7 +983,8 @@ namespace mysql
       {
         os << "// " << c.name () << " base" << endl
            << "//" << endl
-           << "composite_value_traits< " << c.fq_name () << " >::init (o, i);"
+           << "composite_value_traits< " << c.fq_name () <<
+          " >::init (o, i, db);"
            << endl;
       }
     };
@@ -1232,8 +1292,10 @@ namespace mysql
           size_t index (0);
 
           os << "bool " << scope << "::" << endl
-             << "grow (data_image_type&" << (grow ? " i" : "") << ", my_bool* e)"
+             << "grow (data_image_type& i, my_bool* e)"
              << "{"
+             << "ODB_POTENTIALLY_UNUSED (i);"
+             << endl
              << "bool r (false);"
              << endl;
 
@@ -1339,8 +1401,11 @@ namespace mysql
         {
         case ck_ordered:
           {
-            os << "init (index_type& j, value_type& v, const data_image_type& i)"
+            os << "init (index_type& j, value_type& v, " <<
+              "const data_image_type& i, database& db)"
                << "{"
+               << "ODB_POTENTIALLY_UNUSED (db);"
+               << endl
                << "// index" << endl
                << "//" << endl;
 
@@ -1353,8 +1418,11 @@ namespace mysql
         case ck_map:
         case ck_multimap:
           {
-            os << "init (key_type& k, value_type& v, const data_image_type& i)"
+            os << "init (key_type& k, value_type& v, " <<
+              "const data_image_type& i, database& db)"
                << "{"
+               << "ODB_POTENTIALLY_UNUSED (db);"
+               << endl
                << "// key" << endl
                << "//" << endl;
 
@@ -1366,8 +1434,11 @@ namespace mysql
         case ck_set:
         case ck_multiset:
           {
-            os << "init (value_type& v, const data_image_type& i)"
-               << "{";
+            os << "init (value_type& v, const data_image_type& i, " <<
+              "database& db)"
+               << "{"
+               << "ODB_POTENTIALLY_UNUSED (db);"
+               << endl;
             break;
           }
         }
@@ -1375,6 +1446,9 @@ namespace mysql
         os << "// value" << endl
            << "//" << endl;
         {
+          // If the value is an object pointer, pass the id type as a
+          // type override.
+          //
           init_value_member im (
             *this, "value_", "v", vt, "value_type", "value");
           im.traverse (m);
@@ -1485,19 +1559,19 @@ namespace mysql
         {
         case ck_ordered:
           {
-            os << "init (i, v, di);";
+            os << "init (i, v, di, sts.connection ().database ());";
             break;
           }
         case ck_map:
         case ck_multimap:
           {
-            os << "init (k, v, di);";
+            os << "init (k, v, di, sts.connection ().database ());";
             break;
           }
         case ck_set:
         case ck_multiset:
           {
-            os << "init (v, di);";
+            os << "init (v, di, sts.connection ().database ());";
             break;
           }
         }
@@ -1514,9 +1588,9 @@ namespace mysql
              << "{"
              << "if (grow (di, sts.data_image_error ()))"
              << "{"
-             << "binding& db (sts.data_image_binding ());"
-             << "bind (db.bind, 0, di);"
-             << "db.version++;"
+             << "binding& b (sts.data_image_binding ());"
+             << "bind (b.bind, 0, di);"
+             << "b.version++;"
              << "st.refetch ();"
              << "}"
              << "}";
@@ -1589,8 +1663,15 @@ namespace mysql
            << "cb.version++;"
            << "}"
            << "select_statement& st (sts.select_all_statement ());"
-           << "st.execute ();"
-           << "select_statement::result r (st.fetch ());";
+           << "st.execute ();";
+
+        // If we are loading eager object pointers, cache the result
+        // since we will be loading other objects.
+        //
+        if (is_a (m, eager_pointer, vt, "value") || has_a (vt, eager_pointer))
+          os << "st.cache ();";
+
+        os << "select_statement::result r (st.fetch ());";
 
         if (grow)
           os << endl
@@ -1971,8 +2052,10 @@ namespace mysql
         // grow ()
         //
         os << "bool " << traits << "::" << endl
-           << "grow (image_type&" << (grow ? " i" : "") << ", my_bool* e)"
+           << "grow (image_type& i, my_bool* e)"
            << "{"
+           << "ODB_POTENTIALLY_UNUSED (i);"
+           << endl
            << "bool r (false);"
            << endl;
 
@@ -2023,8 +2106,10 @@ namespace mysql
         // init (object, image)
         //
         os << "void " << traits << "::" << endl
-           << "init (object_type& o, const image_type& i)"
-           << "{";
+           << "init (object_type& o, const image_type& i, database& db)"
+           << "{"
+           << "ODB_POTENTIALLY_UNUSED (db);"
+           << endl;
 
         inherits (c, init_value_base_inherits_);
         names (c, init_value_member_names_);
@@ -2163,7 +2248,7 @@ namespace mysql
         {
           os << traits << "::pointer_type" << endl
              << traits << "::" << endl
-             << "find (database&, const id_type& id)"
+             << "find (database& db, const id_type& id)"
              << "{"
              << "using namespace mysql;"
              << endl
@@ -2178,7 +2263,7 @@ namespace mysql
             "pointer_type  >::create ());"
              << "pointer_traits< pointer_type >::guard_type g (p);"
              << "object_type& obj (pointer_traits< pointer_type >::get_ref (p));"
-             << "init (obj, sts.image ());";
+             << "init (obj, sts.image (), db);";
 
           if (containers)
           {
@@ -2197,7 +2282,7 @@ namespace mysql
         }
 
         os << "bool " << traits << "::" << endl
-           << "find (database&, const id_type& id, object_type& obj)"
+           << "find (database& db, const id_type& id, object_type& obj)"
            << "{"
            << "using namespace mysql;"
            << endl
@@ -2208,7 +2293,7 @@ namespace mysql
            << "bool grew (false);"
            << "if (find (sts, id, grew))"
            << "{"
-           << "init (obj, sts.image ());";
+           << "init (obj, sts.image (), db);";
 
         if (containers)
         {
@@ -2303,7 +2388,6 @@ namespace mysql
       traverse_value (type& c)
       {
         bool columns (column_count (c) != 0);
-        bool grow (columns && context::grow (c));
 
         string const& type (c.fq_name ());
         string traits ("access::composite_value_traits< " + type + " >");
@@ -2315,9 +2399,10 @@ namespace mysql
         // grow ()
         //
         os << "bool " << traits << "::" << endl
-           << "grow (image_type&" << (grow ? " i" : "") << ", " <<
-          "my_bool*" << (columns ? " e" : "") << ")"
+           << "grow (image_type& i, my_bool*" << (columns ? " e" : "") << ")"
            << "{"
+           << "ODB_POTENTIALLY_UNUSED (i);"
+           << endl
            << "bool r (false);"
            << endl;
 
@@ -2360,8 +2445,11 @@ namespace mysql
         //
         os << "void " << traits << "::" << endl
            << "init (value_type&" << (columns ? " o" : "") << ", " <<
-          "const image_type&" << (columns ? " i" : "") << ")"
-           << "{";
+          "const image_type&" << (columns ? " i" : "") << ", " <<
+          "database& db)"
+           << "{"
+           << "ODB_POTENTIALLY_UNUSED (db);"
+           << endl;
 
         inherits (c, init_value_base_inherits_);
         names (c, init_value_member_names_);
@@ -2426,9 +2514,16 @@ namespace mysql
            << "#include <odb/mysql/exceptions.hxx>" << endl;
 
     if (ctx.options.generate_query ())
-      ctx.os << "#include <odb/mysql/result.hxx>" << endl
-             << endl
-             << "#include <odb/details/shared-ptr.hxx>" << endl;
+      ctx.os << "#include <odb/mysql/result.hxx>" << endl;
+
+    ctx.os << endl;
+
+    // Details includes.
+    //
+    ctx.os << "#include <odb/details/unused.hxx>" << endl;
+
+    if (ctx.options.generate_query ())
+      ctx.os << "#include <odb/details/shared-ptr.hxx>" << endl;
 
     ctx.os << endl;