SET IDENTITY_INSERT xyz ON 的范围是什么? [英] What is the scope of SET IDENTITY_INSERT xyz ON?

问题描述

SET IDENTITY_INSERT xyz ON 的范围是什么?

如果我在某个表的一个存储过程中使用它，如果运行不同过程的不同用户同时插入到该表中，会发生什么情况?

If I use this in one stored procedure for a certain table, what happens if a different user running a different procedure, inserts into that certain table at the same time?

另外，如果不同的用户/程序尝试设置 SET IDENTITY_INSERT xyz ON同时为不同的表?

Also, what happens if different users/procedures try to set SET IDENTITY_INSERT xyz ON for different tables at the same time?

推荐答案

这是一个会话选项，一张桌子一次只能为任何一张桌子打开这个选项，但多个不同的会话可以为同一张桌子打开这个选项(不是不过这肯定是个好主意！)

It's a session option a table can only have the option on for any one table at a time but multiple different sessions can have it on for the same table (not sure that would ever be a good idea though!)

当子批次完成(设置此选项)时，它看起来会自动取消连接设置.

When a child batch finishes (that sets this option) it looks like it automatically gets unset for the connection.

CREATE TABLE Tst
(C INT IDENTITY(1,1))

EXEC('SET IDENTITY_INSERT Tst ON')
INSERT INTO Tst(C) VALUES (1) /*Fails - Complains IDENTITY_INSERT is off*/

SET IDENTITY_INSERT Tst ON
EXEC('INSERT INTO Tst(C) VALUES (1)') /*Succeeds this way round*/
SET IDENTITY_INSERT Tst OFF


SET IDENTITY_INSERT Tst ON
EXEC('SET IDENTITY_INSERT Tst ON; INSERT INTO Tst(C) VALUES (1);') /* Also succeeds like this*/

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