SQL Error when I try to apply promotion rule

Question

I'm trying to save a catalog price rule and getting the following SQL error:

SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (MY_DB_NAME.catalogrule_group_website, CONSTRAINT catalogrule_group_website_ibfk_1 FOREIGN KEY (rule_id) REFERENCES catalogrule (rule_id) ON DELETE CASCADE ON UPDATE CASCADE)

I was getting this error last night when I was trying to apply a different rule, but it went away and the rule was applied after I reindexed (which may or may not be related).

I tried reindexing a few times today too, no dice. I consistently get this error when I try to apply any rule(s).

I'm not completely SQL ignorant, but am having trouble even beginning to debug. Can anyone point me in the right direction?

On version 1.6.1

Answer 1

A foreign key constraint is there to help with data integrity. They normally fail if you are trying to update one table but do not update a linked table. If you look at the foreign key constraint it will tell you what the linked table is and what value it expects...