The UNLOCK statement releases rows on rows.
<unlock_statement> ::= UNLOCK <row_spec>... IN SHARE MODE
| UNLOCK <row_spec>...
IN EXCLUSIVE MODE
| UNLOCK <row_spec>...
IN SHARE MODE
<row_spec>...
IN EXCLUSIVE MODE
| UNLOCK <row_spec>...
OPTIMISTIC
Using the UNLOCK statement, locks of the following types can be released within a transaction for single table rows that have not yet been changed: share locks, optimistic locks, and exclusive locks.
If a row has not been inserted, changed, or deleted, its exclusive lock cannot be released using the UNLOCK statement.
The unlock statement does not fail if the specified lock does not exist or cannot be released.