<p>The error appears when you attempt to delete rows from a parent table that is still referenced by child rows through a foreign key constraint with ON DELETE RESTRICT or NO ACTION.</p>
<p>MySQL Error 1834: ER_FK_CANNOT_DELETE_PARENT occurs when you try to delete a row in a parent table that is still referenced by a child table's foreign key. Remove or update the dependent child rows first, or alter the constraint to ON DELETE CASCADE, to resolve the issue.</p>
Cannot delete rows from table which is parent in a
MySQL raises error 1834 with SQLSTATE HY000 when a DELETE statement targets a row in a parent table that remains referenced by a foreign key in a child table where the constraint uses RESTRICT or NO ACTION.
The server blocks the operation to maintain referential integrity. The error text typically reads: "Cannot delete rows from table which is parent in a foreign key constraint."
Foreign key constraints guarantee that every child row has a valid parent. Deleting a parent without handling its children would leave orphan records, so MySQL prevents the action unless the constraint is defined with ON DELETE CASCADE or the child rows are removed first.
Before MySQL 5.7.3 the server returned ER_FK_CANNOT_DELETE_PARENT. From 5.7.3 onward, ER_ROW_IS_REFERENCED_2 (error 1451) replaced it, but many applications and logs still reference 1834. The fix strategy is identical across versions.
Repeated failures can break application workflows, lead to partial data updates, and cause user-facing errors. Understanding and correcting the underlying referential issue preserves data integrity and prevents runtime exceptions.
You executed DELETE on the parent table while child rows still exist and the foreign key uses RESTRICT or NO ACTION.
The foreign key was created without ON DELETE CASCADE, so MySQL will not automatically remove dependent rows.
Application logic deletes parent tables first instead of removing or archiving child data beforehand.
Maintenance tasks dropped some child rows but left others, producing an inconsistent state that blocks subsequent parent deletes.
Raised for the same referential delete issue in MySQL 5.7.3 and later.
Occurs when inserting or updating a child row with no matching parent.
Raised when adding a foreign key that conflicts with existing data.
General error thrown when MySQL cannot create a requested foreign key constraint.
Use ON DELETE CASCADE only when business rules allow automatic removal of child rows. Otherwise, delete or reassign child data manually.
SET foreign_key_checks = 0 lets you delete the parent but risks orphaned rows. Re-enable checks immediately and clean up child data.
Starting in MySQL 5.7.3 the server renamed the error to 1451. The root cause and remediation steps are identical.
Galaxy’s schema-aware autocomplete shows existing foreign keys, and its AI copilot can rewrite DELETE statements or suggest cascading constraints, reducing runtime errors.
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