Explain WHEN OTHERS and why you should usually re-raise

WHEN OTHERS THEN matches any exception not caught earlier. A handler that only logs and then falls through (no RAISE) tells the caller the block succeeded when it did not — one of the most common sources of silent data corruption. The safe pattern is: capture SQLERRM and FORMAT_ERROR_BACKTRACE, write them somewhere durable (ideally via an autonomous-transaction logger so the log survives the rollback), then RAISE (or RAISE_APPLICATION_ERROR) so the failure still surfaces.

BEGIN
  -- risky work
  UPDATE accounts SET balance = balance - 100 WHERE account_id = -1;
  IF SQL%ROWCOUNT = 0 THEN RAISE NO_DATA_FOUND; END IF;
EXCEPTION
  WHEN OTHERS THEN
    err_log_pkg.record(SQLCODE, SQLERRM, DBMS_UTILITY.FORMAT_ERROR_BACKTRACE);
    RAISE;                       -- do NOT stop here
END;
/