+local function debugwrap(name, f)
+ return function (self, sql, ...)
+ debugquery(name, sql, ...)
+ return f(self, sql, ...)
+ end
+end
+function engine:debug(enable)
+ self._debug = enable;
+ if enable then
+ engine.insert = debugwrap("insert", engine.execute_update);
+ engine.select = debugwrap("select", engine.execute_query);
+ engine.delete = debugwrap("delete", engine.execute_update);
+ engine.update = debugwrap("update", engine.execute_update);
+ else
+ engine.insert = engine.execute_update;
+ engine.select = engine.execute_query;
+ engine.delete = engine.execute_update;
+ engine.update = engine.execute_update;
+ end
+end
+local function handleerr(err)
+ log("error", "Error in SQL transaction: %s", debug_traceback(err, 3));
+ return err;
+end