Re: How to create a before update trigger for 2 fields "expected_hash" and "identify_hash" (both allow null)

[Peter Brawley]

> IF (new.identify_hash = clientdb_mapping.expected_hash) THEN

If this is intended to reference the current row value of clientdb_mapping.expected_hash, use OLD.expected_hash.

> -- UPDATE clientdb_mapping SET identify_hash = clientdb_mapping.expected_hash;

Re-read the manual page on Triggers. An Update Trigger may not invoke Update on the table for which it's defined (obviously, since it would thus begin an infinite regress). Instead, write ...

SET new.identity_hash=old.expected_hash;

> DELETE FROM pi_hash_migration_mapping;

That cmd will delete all rows from pi_hash_migration_mapping. Is that intended?