* change connection of mariadb driver

include/cpphibernate/driver/mariadb/mariadb.h

@@ -12,14 +12,14 @@ beg_namespace_cpphibernate_driver_mariadb
     struct mariadb_driver_t
     {
     private:
-        ::cppmariadb::connection&   _connection;
+        ::cppmariadb::connection*   _connection;
         schema_t                    _schema;
         filter_t                    _filter;
 
     public:
         template<typename T_schema>
         mariadb_driver_t(T_schema&& p_schema, ::cppmariadb::connection& p_connection)
-            : _connection   (p_connection)
+            : _connection   (&p_connection)
             , _schema       (make_schema(std::forward<T_schema>(p_schema)))
             { }
 
@@ -27,7 +27,10 @@ beg_namespace_cpphibernate_driver_mariadb
         cpphibernate_moveable(mariadb_driver_t, default);
 
         inline const ::cppmariadb::connection& connection() const
-            { return _connection; }
+            { return *_connection; }
+
+        inline void connection(::cppmariadb::connection& p_connection)
+            { _connection = &p_connection; }
 
         template<typename... T_args>
         inline void set_filter_inclusive(T_args&&... args)
@@ -43,8 +46,8 @@ beg_namespace_cpphibernate_driver_mariadb
     protected:
         inline void init_impl(bool recreate) const
         {
-            transaction_lock trans(_connection);
-            _schema.init(init_context(_schema, _connection, recreate));
+            transaction_lock trans(*_connection);
+            _schema.init(init_context(_schema, *_connection, recreate));
             trans.commit();
         }
 
@@ -52,7 +55,7 @@ beg_namespace_cpphibernate_driver_mariadb
         inline void create_impl(T_dataset& dataset) const
         {
             create_update_impl_t<T_dataset>::apply(
-                create_update_context(dataset, _schema, _connection, _filter, false));
+                create_update_context(dataset, _schema, *_connection, _filter, false));
         }
 
         template<typename T_dataset, typename T_modifiers>
@@ -63,12 +66,12 @@ beg_namespace_cpphibernate_driver_mariadb
 
             auto  dataset_id = misc::get_type_id(hana::type_c<real_dataset_type>);
             auto& table      = _schema.table(dataset_id);
-            auto  context    = make_read_context(dataset, _schema, _connection, _filter);
-            context.where    = build_where(_schema, modifiers).query(_connection);
-            context.limit    = build_limit(modifiers).query(_connection);
-            context.order_by = build_order_by(_schema, modifiers).query(_connection);
+            auto  context    = make_read_context(dataset, _schema, *_connection, _filter);
+            context.where    = build_where(_schema, modifiers).query(*_connection);
+            context.limit    = build_limit(modifiers).query(*_connection);
+            context.order_by = build_order_by(_schema, modifiers).query(*_connection);
 
-            transaction_lock trans(_connection);
+            transaction_lock trans(*_connection);
             table.read(context);
             trans.commit();
         }
@@ -77,7 +80,7 @@ beg_namespace_cpphibernate_driver_mariadb
         inline void update_impl(T_dataset& dataset) const
         {
             create_update_impl_t<T_dataset>::apply(
-                create_update_context(dataset, _schema, _connection, _filter, true));
+                create_update_context(dataset, _schema, *_connection, _filter, true));
         }
 
         template<typename T_dataset>
@@ -89,7 +92,7 @@ beg_namespace_cpphibernate_driver_mariadb
             auto  dataset_id = misc::get_type_id(hana::type_c<real_dataset_type>);
             auto& table      = _schema.table(dataset_id);
 
-            destroy_context context(dataset, _schema, _connection);
+            destroy_context context(dataset, _schema, *_connection);
             context.where = table.get_where_primary_key(context);
 
             destroy_impl_t<T_dataset>::apply(context);