Manual:Actor table

The actor table is where MediaWiki stores information about actors, factored out from the revision, logging and image tables in T167246.

actor_id
actor_id is the primary key, used to uniquely identify an actor.

actor_user
actor_user is a key to  of the user who made the action, or   for logged-out (IP) edits and for some mass imports.

actor_name
actor_name is the text of the username or the IP address of the actor.

Schema summary
++-+--+-+-++ | Field     | Type                | Null | Key | Default | Extra          | ++-+--+-+-++ | actor_id  | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment | | actor_user | int(10) unsigned   | YES  | UNI | NULL    |                | | actor_name | varbinary(255)     | NO   | UNI | NULL    |                | ++-+--+-+-++