Are foreign keys really necessary in a database design?

Question

As far as I know, foreign keys (FK) are used to aid the programmer to manipulate data in the correct way. Suppose a programmer is actually doing this in the right manner alr

Answer 1

I can't imagine designing a database without foreign keys. Without them, eventually you are bound to make a mistake and corrupt the integrity of your data.

They are not required, strictly speaking, but the benefits are huge.

I'm fairly certain that FogBugz does not have foreign key constraints in the database. I would be interested to hear how the Fog Creek Software team structures their code to guarantee that they will never introduce an inconsistency.