I get the following error message when I try to INSERT some data:
SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or
update a child row: a foreign key constraint fails
(database/UserDetails, CONSTRAINTUserDetails_ibfk_6FOREIGN
KEY (HearAboutID) REFERENCESUserDetails(HearAboutID) ON DELETE
CASCADE ON UPDATE CASCADE)
The FK relationship looks like this:

The data I’m trying to enter into UserDetails.HearAboutID is present in UserHearAbout.UserHearAboutID… so why won’t it go? 🙁
From the error you posted
(you actually created a constraint that refers to the same table and same column),
I guess that your FK constraint definition is wrong (it should be