sql – 行锁 – 手动使用它们

我基本上有一个应用程序,有5个线程,每个都从表中读取.查询是表中的一个简单的SELECT TOP 1 *,但我想强制执行锁定,以便下一个线程将从表中选择下一条记录而不是锁定的记录.当应用程序完成任务后,它将更新锁定的记录并释放锁定并再次重复该过程.这可能吗？

解决方法

BEGIN TRANSACTION

-- Find the next available record that's not already being processed.
-- The combination of UPDLOCK and READPAST hints makes sure 2 processes don't 
-- grab the same record,and that processes don't block each other.
SELECT TOP 1 @ID = ID
FROM YourTable WITH (UPDLOCK,READPAST)
WHERE BeingProcessed = 0

-- If we've found a record,set it's status to "being processed"
IF (@ID IS NOT NULL)
    UPDATE YourTable SET BeingProcessed = 1 WHERE ID = @ID

COMMIT TRANSACTION

-- Finally return the record we've picked up
IF (@ID IS NOT NULL)
    SELECT * FROM YourTable WHERE ID = @ID

有关这些表提示的更多信息,请参阅MSDN

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