SQL Server:"非常独特"的索引

Question

在表中,我想确保在五列密钥上只存在唯一的值:

Timestamp Account RatingDate TripHistoryKey EventAction
========= ======= ========== ============== ===========
2010511   1234    2010511    1              INSERT
2010511   1234    2010511    4              INSERT
2010511   1234    2010511    7              INSERT
2010511   1234    2010511    1              INSERT   <---duplicate

但我只希望唯一约束,以行之间适用时EventAction是INSERT:

Timestamp Account RatingDate TripHistoryKey EventAction
========= ======= ========== ============== ===========
2010511   1234    2010511    1              INSERT
2010511   1234    2010511    1              UPDATE
2010511   1234    2010511    1              UPDATE   <---not duplicate
2010511   1234    2010511    1              UPDATE   <---not duplicate
2010511   1234    2010511    1              DELETE   <---not duplicate
2010511   1234    2010511    1              DELETE   <---not duplicate
2010511   1234    2010511    1              INSERT   <---DUPLICATE

可能？

Answer 1

是

• SQL Server 2008:使用筛选索引
• SQL Server 2005:使用触发器或索引视图

编辑:

• 索引视图示例