Error Code 1451 occurs in MySQL when trying to delete a record that's still being referenced by a foreign key in another table. To resolve this:

1. Check Foreign Key Constraints: Inspect the foreign key relationships using SHOW CREATE TABLE and information_schema.KEY_COLUMN_USAGE.

2. Delete or Update Dependent Records: Before deleting the parent record, remove or update any dependent records in the child table using commands like DELETE or UPDATE.

3. Use CASCADE: Modify the foreign key to include ON DELETE CASCADE or ON UPDATE CASCADE, which automatically deletes or updates dependent records when the parent changes.

4. Remove Orphaned Data: Identify and delete orphaned child records that no longer reference a parent, ensuring referential integrity.

These steps should help you resolve the error.