Oracle Database / SQL & PL/SQL Errors
ORA-02291: investigate a missing parent key
A child insert or update can fail when its referenced parent does not exist in the transaction's visible data. Identify the foreign key and referenced constraint.
Environment and inputs: Oracle Database 19c baseline · SQL*Plus-compatible SQL unless RMAN, DGMGRL, ADRCI or a host shell is specified. Check release, patch level, edition and container first.
Start with this diagnostic
Use the stated SQL, RMAN, DGMGRL or host shell and replace sample names with approved targets. DBA and V$ views need authorized catalog access in the correct container. Do not grant broad privileges for an example.
SELECT owner, constraint_name, table_name, r_owner, r_constraint_name FROM all_constraints WHERE owner = 'APP_OWNER' AND constraint_name = 'FK_ORDER_CUSTOMER';Read the result
The referenced owner and constraint lead to the parent key. The child value itself must come from the application's authorized evidence.
Resolve and verify
Verify the parent identifier, transaction ordering and environment. Correct the request or load order and retest the complete parent-child operation.
Operational precautions
Do not disable referential integrity to accept orphan rows as a support shortcut.