Delete raises integrity error

Question

I have 2 tables:

• Users with U_Id as primary key
• Votes with V_author which refers to Users(U_Id) as foreign key

Question: How to delete rows from Users table? When I try to do that I get the error below.

Error: psycopg2.IntegrityError: update or delete on table "users" violates foreign key constraint "votes_v_author_fkey" on tabl e "votes" DETAIL: Key (u_id)=(7) is still referenced from table "votes".

Answer 1

As described in the error, there is a record in Votes table, which refers to about to be deleted record from Users table. You need to delete the records from child table first:

DELETE FROM Votes WHERE v_author = 7