删除主键也删除外键。

I have two table, with a PK of ID. If say I delete the entry for ID = 1, I want it to automatically delete the FK of ID in the other table. In other words I want so that it should also delete all entries with ID = 1 in the other table. How can I do this? I have linked the PK-FK relationship, but when I delete the entry with ID 1 in the PK table it doesn't delete the FK.I have two table, with a PK of ID. If say I del