Referential Integrity

FOG 1.5 has no database-level foreign key enforcement. Cleanup after a delete is PHP’s job there, and nothing stops an orphaned reference. 1.6 documents what actually happens when you delete a record other rows point at.

Which version am I on?

Check FOG Configuration → FOG Settings → General → FOG_VERSION in the web UI, or the version string printed at the top of installfog.sh.