problem in insert using adoconnection

We are doing a migration of the database of the system of firebird to sql server and we put an adoconnection ... we have a table of client that makes a join with the table of cities ... the problem is that now that we insert a register in the customer table he tries to insert a new record in the tbm cities table, and when we exclude a client he tbm excludes from the city table the city referring to the client's city code ... someone has already gone through this and can help ?? vlw