Thanks Dan, Let me try it. SQLite is giving me a real tough time. Oops! It works!! Thank you very much. Mr. Dan, please I have another question, I was hoping to post my question one after the other. I will drop it here too. I created tables with primary and foreign keys using my SQLite Studio, the foreign keys are enabled already. I noticed that when I populate my tables from my python application GUI, the foreign keys constraints are not maintained, they are violated and the records get saved successfully. When I run the same program connected to MySQL or MSSQL database tables with the foreign keys too, invalid data which do not match with data of the PK columns are rejected with a notification stating that the foreign key constraint is not met. I noticed when I decide to populate the tables directly from SQLite studio, the foreign keys constraints are upheld and invalid data which do not exist in the PK columns are rejected. So why does SQLite accept invalid data populated through Python program?