有没有一种方法可以测试DELETE是否会由于约束而失败？

我希望能够预测DELETE是否会遇到约束违例，而无需实际执行删除操作。

我有什么选择呢？有没有简单的方法可以对DELETE进行“空运行”？

如果您的目标是仅在所有删除均成功的情况下处理所有删除，为什么不使用TRY / CATCH：

BEGIN TRANSACTION;
BEGIN TRY
  DELETE #1;
  DELETE #2;
  DELETE #3;
  COMMIT TRANSACTION;
END TRY
BEGIN CATCH
  ROLLBACK TRANSACTION;
END CATCH

如果目标是即使一个或多个失败都会允许所有成功的删除成功，则可以使用单独的TRY / CATCH，例如

BEGIN TRY
  DELETE #1;
END TRY
BEGIN CATCH
  PRINT 1;
END CATCH

BEGIN TRY
  DELETE #2;
END TRY
BEGIN CATCH
  PRINT 1;
END CATCH

一种选择是开始事务，运行删除，然后始终回滚：

begin tran

delete Table1 where col1 = 1

-- Test whether it is there
select * from Table1 where col1 = 1

rollback tran

-- Confirm that it is still there
select * from Table1 where col1 = 1

我想用一些代码来改进Aaron Bertrand提供的解决方案，以防您想要尝试添加表的任何元素，管理异常以忽略失败或也可以在错误之后停止进程。

这将从表中选择记录，然后尝试删除它们，无例外：

DECLARE @MaxErrors INT
SET @MaxErrors = 5;    // Setting 0 will stop process after the first error!

SELECT
    [Id]
    , ROW_NUMBER() OVER (ORDER BY Id ASC) AS [Index]
INTO #DeletingItems
FROM myTable

DECLARE @Current INT, @Max INT, @Id INT, @TotErrors INT
SELECT
    @Current = 1
    , @TotErrors = 0
    , @Max = MAX([Index])
FROM #DeletingTable

WHILE @Current <= @Max
BEGIN
    SELECT
        @Id = [Id]
    FROM #DeletingItems
    WHERE
        [Index] = @Index;

    BEGIN TRANSACTION;    
    BEGIN TRY    
        DELETE FROM myTable WHERE [Id] = @Id;

        COMMIT TRANSACTION;    
    END TRY    
    BEGIN CATCH    
        ROLLBACK TRANSACTION;

        SET @TotErrors = @TotErrors + 1;

        IF @TotErrors > @MaxErrors
            BREAK;
    END CATCH

    SET @Current = @Current + 1;
END