Hi,
I have my datasource and business class. Every Business class will create an instance of datasource class.

I have question that, if I have sales business class. It will access sales and sales details table. Should I create an instance of datasource class, and an instance of sales datasource? Or any other ideas?

If I wan to delete a cashier, the sales transaction done by the cashier should not be deleted. I know I can set integrity relationship for cascade delete or etc. But how about both of these tables are from different database? Therefore, I think I should implement the cascade delete in class either. WHere should I place this codes, deletestaff method or.. ? How do you do?

Thank you