hi, I am inserting data in to two tables table1 and table2. for that created two methods one for insert data into table1 and the other is used to insert data into table2 If I call these two methods one by one then it is successfully inserting.. If I call the first method using thread (NSThread detachNewThreadSelector...) and the other calling by next instruction , then error occured *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Error: failed to prepare statement with message 'library routine called out of sequence'.' I am using same sqlite3 instance for both method.. let me know whats the issue ? or doesn't sqlite support simultaneous insertion (inserting diff. tables) ?