Why Does Attempting to Remove a Foreign Key in MySQL Using the Index Name Result in an Error?

Error: Removing a Foreign Key in MySQL with Index Name

When attempting to remove a foreign key column from a table, you may encounter an error if you specify the index name instead of the constraint name.

In the given example, the query to drop the foreign key constraint locationIDX using the index name results in the error:

ERROR 1025 (HY000): Error on rename

Solution: Drop Foreign Key by Constraint Name

To successfully drop the column, use the constraint name as follows:

ALTER TABLE assignment DROP FOREIGN KEY locationIDX;

Reason

In MySQL, foreign key constraints are referenced by their names, not by the names of their associated indexes. By specifying the constraint name, you ensure that the correct constraint is removed without affecting other indexes or relationships in the database.

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