Scope_Identity()、Identity()、@@Identity 和 Ident_Current() 之间有什么区别? [英] What is the difference between Scope_Identity(), Identity(), @@Identity, and Ident_Current()?
问题描述
我知道 Scope_Identity()、Identity()、@@Identity 和 Ident_Current() 所有获取标识列的值，但我很想知道其中的区别.
I know Scope_Identity(), Identity(), @@Identity, and Ident_Current() all get the value of the identity column, but I would love to know the difference.
我遇到的部分争议是，它们所指的适用于上述这些功能的范围是什么意思?
Part of the controversy I'm having is what do they mean by scope as applied to these functions above?
我也喜欢使用它们的不同场景的简单示例?
I would also love a simple example of different scenarios of using them?
推荐答案
@@identity函数返回在同一会话中创建的最后一个身份.scope_identity()函数返回在同一会话和同一范围内创建的最后一个身份.ident_current(name)返回为任何会话中的特定表或视图创建的最后一个标识.identity()函数不用于获取身份，而是用于在select...into查询中创建身份.- The
@@identityfunction returns the last identity created in the same session. - The
scope_identity()function returns the last identity created in the same session and the same scope. - The
ident_current(name)returns the last identity created for a specific table or view in any session. - The
identity()function is not used to get an identity, it's used to create an identity in aselect...intoquery.
会话是数据库连接.作用域是当前查询或当前存储过程.
The session is the database connection. The scope is the current query or the current stored procedure.
scope_identity() 和 @@identity 函数不同的情况是，如果您在表上有触发器.如果您有一个插入记录的查询，导致触发器在某处插入另一条记录，scope_identity() 函数将返回查询创建的标识，而 @@identity 函数将返回触发器创建的标识.
A situation where the scope_identity() and the @@identity functions differ, is if you have a trigger on the table. If you have a query that inserts a record, causing the trigger to insert another record somewhere, the scope_identity() function will return the identity created by the query, while the @@identity function will return the identity created by the trigger.
因此，通常您会使用 scope_identity() 函数.
So, normally you would use the scope_identity() function.
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