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 Releasing Locks 

The locks assigned to a transaction are usually released at the end of the transaction, making the respective database objects accessible again to other transactions.

The following rules apply:

·        The locks requested by the LOCK statement are usually released when the transaction ends, provided that the COMMIT statements or the ROLLBACK statements that end a transaction do not also contain a LOCK statement.

·        The length of time for which an implicit shared lock is held depends on the isolation level.

·        Exclusive locks for rows that have not yet been modified and shared locks on rows can be released by the UNLOCK statement before the end of the transaction.

·        Exclusive locks set implicitly cannot be released within a transaction.

·        Exclusive locks on updated rows, exclusive locks that were requested by an SQL statement that leads to a change (INSERT, UPDATE, DELETE), and table blocks cannot be released within a transaction, only after the transaction has ended.

 

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