A PL/SQL RAISE_APPLICATION_ERROR (ORA-20000 to ORA-20999): its number
and message, without the ORA-20xxx: prefix and the ORA-06512 stack
lines. Its code is CONFLICT (409), and the message is for the client.
The database's or the driver's code: 'ORA-00001', 'NJS-040', 'NJS-123'…
The ORA error number of the failure, if the database reported one.
Whether web-kit shows the message to the client: a PL/SQL application error's.
The statement ran out of time: node-oracledb's callTimeout (NJS-123) or the driver's deadline.
A row could not be converted to what its spec or schema says. The column is named; the value stays out of the message (it may be personal data).