What is a proper naming convention for MySQL FKs?

Question

Being that they must be unique, what should I name FK\'s in a MySQL DB?

Answer 1

my choice is different. in my opinion, a table should have an id field, not a user_id one, because table is just called user, so:

CREATE TABLE users(
   id    int,
   name       varchar(100)
);

CREATE TABLE messages(
   id int,
   user_id    int
);

user_id in messages table is a fk field so it has to make clear which id is (user_id).

a fully-self-explaining naming convention, in my opinion, could be:

fk_[referencing table name]_[referencing field name]_[referenced table name]_[referenced field name]

i.e.: `fk_messages_user_id_users_id`

note:

• you can, in some case, omit the second element ([referencing field name])

• this fk could is unique, because if a messages_user table exists, the referencing field name should be user_id (and not just id) and the fk name should be:

  fk_messages_user_user_id_users_id

in other words, a foreign key naming convention make you sure about unique names if you also use a "referencing/referenced field" naming convention (and you can choose your own, of course).