MySQL Error 1215: Cannot add foreign key constraint

Question

I am trying to forward engineer my new schema onto my db server, but I can\'t figure out why I am getting this error. I\'ve tried to search for the answer here, but everyth

Answer 1

In my case, I had deleted a table using SET FOREIGN_KEY_CHECKS=0, then SET FOREIGN_KEY_CHECKS=1 after. When I went to reload the table, I got error 1215. The problem was there was another table in the database that had a foreign key to the table I had deleted and was reloading. Part of the reloading process involved changing a data type for one of the fields, which made the foreign key from the other table invalid, thus triggering error 1215. I resolved the problem by dropping and then reloading the other table with the new data type for the involved field.