When DB2 performs an index or table scan, DB2 will block on a row lock when it comes across an uncommitted row which another transaction has exclusively (X) locked.

DB2 在执行索引或表扫描时，如果遇到一个被另一个事务独占 (X) 锁定的未提交行，那么 DB2 将阻塞在行锁上。

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Somewhat obviously, they can be used to check the validity of a block of data such as a journal transaction.

显而易见，这种方式也可以被用来检查写入数据(比如日志事务)的有效性。

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If something goes wrong, the catch block rolls back all changes made since the transaction was started, and then prints out an error message.

如果发生了错误，catch块可以回滚事务开始以来发生的所有更改，并打印出一条错误消息。

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The Justice Department and Federal Communications Commission had antitrust worries about the deal, and the Justice Department had filed suit to block the transaction.

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Payment providers, especially mobile payment providers, claim to represent the best in consumer-centric solutions, but if they truly care about consumers, why do they block so many important transaction types that consumers want?

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So this may be more about financial engineering than anything else and may be the stumbling block to get in the way of an actual transaction.

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