Thanks for Answers
now i know more about foreign keys ,
i have a question refering to the two tables of my previous message (tBanks , tCustomers) :
i want the user cannot delete a tBanks record if it exists in the tCustomers table .

No other constraints , e.g. a tCustomer record can be not connected to any tBanks record .
...using foreign keys , i can't leave a tCustomer record without a tBanks record connected .

can i do that only with triggers ?

thanks

Maurizio

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