SQL服务器，同时双插入，unicity Bug

Question

当下面的代码几乎同时被调用两次时，我遇到了麻烦。

DECLARE @membershipIdReturn as uniqueidentifier=null
SELECT @membershipIdReturn = MembershipId 
FROM [Loyalty].[Membership] 
WITH (NOLOCK)
WHERE ContactId = @customerIdFront 
AND 
IsDeleted = 0

IF (@membershipIdReturn IS NULL)
  //InsertStatementHere

调用非常接近（大约千分之三秒），第二次调用也进入了 if 语句。然后解除单一性故障，因为这是不应该发生的。

是因为(NOLOCK)的bug吗？我需要它来解决交易问题。

是否有解决此问题的解决方法？

谢谢艾尔

Answer 1

两个选项

1.Use 唯一约束然后将您的插入语句放入 Try Catch 块

ALTER TABLE [Loyalty].[Membership] 
ADD CONSTRAINT uc_ContactId_IsDeleted UNIQUE(ContactId, IsDeleted)

2.Use 与可序列化提示合并。因此，select和insert.

之间不会有空隙

MERGE   [Loyalty].[Membership] WITH (SERIALIZABLE) as T 
USING   [Loyalty].[Membership] as S
ON      ContactId = @customerIdFront 
        AND IsDeleted = 0
WHEN NOT MATCHED THEN
INSERT (MemberName, MemberTel) values ('','');

SQL服务器，同时双插入，unicity Bug

SQL Server, double insert at the exact same time, unicity Bug

sql-server

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sql-server-2012