In SQL Server, how can I lock a single row in a way similar to Oracle's "SELECT FOR UPDATE WAIT"?

Solution 1:

You're probably looking forwith (updlock, holdlock). This will make a select grab an exclusive lock, which is required for updates, instead of a shared lock. The holdlock hint tells SQL Server to keep the lock until the transaction ends.

FROM TABLE_ITEM with (updlock, holdlock)

Solution 2:

As documentation sayed:

XLOCK

Specifies that exclusive locks are to be taken and held until the transaction completes. If specified with ROWLOCK, PAGLOCK, or TABLOCK, the exclusive locks apply to the appropriate level of granularity.

So solution is using WITH(XLOCK, ROWLOCK):

BEGIN TRANSACTION;

SELECT ITEM_ID
FROM TABLE_ITEM
WITH(XLOCK, ROWLOCK)
WHERE ITEM_PRIORITY > 10 AND ITEM_CATEGORY = 'CT1' AND ITEM_STATUS = 'available' AND ROWNUM = 1;

UPDATE [locked item_id] SET ITEM_STATUS = 'unavailable';

COMMIT TRANSACTION;

Solution 3:

In SQL Server there are locking hints but they do not span their statements like the Oracle example you provided. The way to do it in SQL Server is to set an isolation level on the transaction that contains the statements that you want to execute. See this MSDN page but the general structure would look something like:

SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;

BEGIN TRANSACTION;

    select * from ...

    update ...

COMMIT TRANSACTION;

SERIALIZABLE is the highest isolation level. See the link for other options. From MSDN:

SERIALIZABLE Specifies the following:

Statements cannot read data that has been modified but not yet committed by other transactions.

No other transactions can modify data that has been read by the current transaction until the current transaction completes.

Other transactions cannot insert new rows with key values that would fall in the range of keys read by any statements in the current transaction until the current transaction completes.