Re: Possible to delete record from all tables at the same time?

mwsenecal@yahoo.com writes:
> Is it possible to delete a record from all tables in the database at
> the same time, without having to execute a separate "DELETE" statement
> for each table?
>
> I have a situation where I need to delete user records from our system.
> The user account information is spread across a handful of tables. Each
> table has an "id" field that contains the user's id, so the tables do
> have one field in common. When purging a user account from the system,
> I'd like to be able to issue one command that will delete the user
> account information from all tables, rather than issue separate delete
> commands for each table, something along the lines of:
>
>    DELETE FROM ALL_TABLES WHERE userId = "whatever";
>
> Is this possible?

Yes, it is, though not via that mechanism.

<http://www.postgresql.org/docs/current/static/ddl-constraints.html>

This would be handled via a set of foreign keys of the "ON DELETE
CASCADE" sort.

Thus, you'd have one central "user" account, with the id field.

A table associating users with privileges might look like the
following:

CREATE TABLE user_privileges (   privilege_no integer REFERENCES privileges ON DELETE RESTRICT,   user_id integer
REFERENCESuser(id) ON DELETE CASCADE,   primary key (privilege_no, user_id)
 
);

Other tables would similarly reference "user(id) ON DELETE CASCADE";
whenever you delete from table user, the corresponding entries in
those tables would automatically be deleted.
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