# 3757 Altering a Primary Key Constraint that is the Target of Foreign Key Constraints Disables Checks

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If a primary key contraint is altered in any way (eg even just adding to the description) using EDB Manager, then any foreign key constraints in other tables that use this index appear to be broken.

For example in my database, table acManufacturer has a primary key contraint pkManufacturerCode. The acStock table uses this as a lookup table using a foreign key constraint (fkManufacturerCode). Try to delete a manufacturer that is being used in an acStock record (in my attached sample code = 'NORTON') and the appropriate exception is raised.

Now make a trivial change to acManufacturer's primary key, say add something to the description. then try the delete again and this time it succeeds - the constraint has not been applied. If, after the primary key is altered, a trivial change is also applied to acStock's fkManufacturerCode foreign key constraint as well and then try the delete all is well and a constraint exception is raised.