diff --git a/orm_lib/src/mysql_impl/MysqlConnection.cc b/orm_lib/src/mysql_impl/MysqlConnection.cc
index 61d588e9..6681926d 100644
--- a/orm_lib/src/mysql_impl/MysqlConnection.cc
+++ b/orm_lib/src/mysql_impl/MysqlConnection.cc
@@ -434,10 +434,10 @@ void MysqlConnection::outputError()
         catch (...)
         {
             _exceptCb(std::current_exception());
-            _exceptCb = decltype(_exceptCb)();
+            _exceptCb = nullptr;
         }
 
-        _cb = decltype(_cb)();
+        _cb = nullptr;
         _isWorking = false;
         if (_idleCbPtr)
         {
@@ -457,8 +457,8 @@ void MysqlConnection::getResult(MYSQL_RES *res)
     if (_isWorking)
     {
         _cb(Result);
-        _cb = decltype(_cb)();
-        _exceptCb = decltype(_exceptCb)();
+        _cb = nullptr;
+        _exceptCb = nullptr;
         _isWorking = false;
         if (_idleCbPtr)
         {
diff --git a/orm_lib/src/postgresql_impl/PgConnection.cc b/orm_lib/src/postgresql_impl/PgConnection.cc
index 39b1e20a..bfbe5794 100644
--- a/orm_lib/src/postgresql_impl/PgConnection.cc
+++ b/orm_lib/src/postgresql_impl/PgConnection.cc
@@ -197,9 +197,9 @@ void PgConnection::execSqlInLoop(std::string &&sql,
                 {
                     auto exceptPtr = std::current_exception();
                     _exceptCb(exceptPtr);
-                    _exceptCb = decltype(_exceptCb)();
+                    _exceptCb = nullptr;
                 }
-                _cb = decltype(_cb)();
+                _cb = nullptr;
                 if (_idleCbPtr)
                 {
                     auto idle = std::move(_idleCbPtr);
@@ -237,9 +237,9 @@ void PgConnection::execSqlInLoop(std::string &&sql,
                     {
                         auto exceptPtr = std::current_exception();
                         _exceptCb(exceptPtr);
-                        _exceptCb = decltype(_exceptCb)();
+                        _exceptCb = nullptr;
                     }
-                    _cb = decltype(_cb)();
+                    _cb = nullptr;
                     if (_idleCbPtr)
                     {
                         auto idle = std::move(_idleCbPtr);
@@ -268,9 +268,9 @@ void PgConnection::execSqlInLoop(std::string &&sql,
                     {
                         auto exceptPtr = std::current_exception();
                         _exceptCb(exceptPtr);
-                        _exceptCb = decltype(_exceptCb)();
+                        _exceptCb = nullptr;
                     }
-                    _cb = decltype(_cb)();
+                    _cb = nullptr;
                     if (_idleCbPtr)
                     {
                         auto idle = std::move(_idleCbPtr);
@@ -312,9 +312,9 @@ void PgConnection::execSqlInLoop(std::string &&sql,
                         {
                             auto exceptPtr = std::current_exception();
                             thisPtr->_exceptCb(exceptPtr);
-                            thisPtr->_exceptCb = decltype(thisPtr->_exceptCb)();
+                            thisPtr->_exceptCb = nullptr;
                         }
-                        thisPtr->_cb = decltype(thisPtr->_cb)();
+                        thisPtr->_cb = nullptr;
                         if (thisPtr->_idleCbPtr)
                         {
                             auto idle = std::move(thisPtr->_idleCbPtr);
@@ -349,9 +349,9 @@ void PgConnection::handleRead()
             {
                 auto exceptPtr = std::current_exception();
                 _exceptCb(exceptPtr);
-                _exceptCb = decltype(_exceptCb)();
+                _exceptCb = nullptr;
             }
-            _cb = decltype(_cb)();
+            _cb = nullptr;
             if (_idleCbPtr)
             {
                 //auto idle = std::move(_idleCbPtr);
@@ -388,9 +388,9 @@ void PgConnection::handleRead()
                 catch (...)
                 {
                     _exceptCb(std::current_exception());
-                    _exceptCb = decltype(_exceptCb)();
+                    _exceptCb = nullptr;
                 }
-                _cb = decltype(_cb)();
+                _cb = nullptr;
             }
         }
         else
@@ -405,8 +405,8 @@ void PgConnection::handleRead()
                 {
                     auto r = makeResult(res, _sql);
                     _cb(r);
-                    _cb = decltype(_cb)();
-                    _exceptCb = decltype(_exceptCb)();
+                    _cb = nullptr;
+                    _exceptCb = nullptr;
                 }
             }
         }
@@ -416,7 +416,7 @@ void PgConnection::handleRead()
         if (isPreparing)
         {
             _preparingCallback();
-            _preparingCallback = std::function<void()>();
+            _preparingCallback = nullptr;
         }
         else
         {