Hi,
I am researching about the methodolofgy of building N-Tier client server system.
I would like to ask that:

1. Where should I place the code of enforce the integrity between 2 or more tables? e.g., If I have one-many relationship tables. Once user need to delete the master record, I need to check the any exisiting child records related to the master. I should call the function (check integrity) in my Master object (e.g. customer), a new object (e.g. customerBooking), call it directly in User sevice, place it as stored procedure or define the integrity in DBMS and trap the error ??

2. How about insert function as the situation above?

Thank you