Detailed description on how to prevent Concurrent Insertion of duplicate data in SQL Server

Detailed description on how to prevent Concurrent Insertion of duplicate data in SQL Server

SQL Server prevents Concurrent Insertion of duplicate data by using the following methods:

1. Duplicate data cannot be inserted at the database level using Primary Key and Unique Key.

2. Conditions for use during insertion

Insert into Table (***) select ***** where not exists (select 1 from Table where ****);

3. Use SERIALIZABLE isolation level, and use updlock or xlock lock prompts (equivalent to using (updlock, holdlock) or (xlock, holdlock) at the default isolation level ))

Set transaction isolation level SERIALIZABLEBegin Tran select 1 from Table with (UPDLOCK) where ***** -- if the index is supported, range lock RangeS-U is added, although it can be locked, the concurrency performance is not good. If @ ROWCOUNT = 0 insert into Table (*****) values (*****); Commit Tran

The above is all the content of this article. I hope this article will help you in your study or work. I also hope to provide more support to the customer's home!