I am looking at users table of a moodle site which has been upgraded several times over times and now it is 2.5.
While looking at mdl_user table I noticed that some users have the value "-1" for the field "deleted".
as far as I know, when a user is deleted, the "deleted" field in the database will change to 1, not -1.
Also I noticed that these users (with -1 value in their deleted field) have full data. I mean their firstname, lastname, email, etc are correct. And I know that if Moodle deletes a user, it scrambles the real data.
Can someone please give me an idea how the "deleted" field has got -1 value? probably someone made manual changes to the database?