MySQL auto increments disappeared

Question

I have a mysql database with 60 tables most of the tables have primary keys (expect pivot tables) all these primary keys had the attribute AUTO INCREMENT

Then over night some how all the primary keys had that attribute removed, and the default value set to 0.

I have no idea how this may have been caused. Any suggestions?

Answer 1

Improper backup/restore probably. I've recently learned that mysqldump with --skip-opt option will drop auto-increment index :(