如果代码命中内部catch块,则RETURN代码默认为-4而不是0

有谁知道这来自哪里？供参考

干杯
GBN

IF OBJECT_ID('dbo.foo') IS NOT NULL DROP TABLE dbo.foo
GO
CREATE TABLE dbo.foo (
    KeyCol  char(12) NOT NULL,ValueCol xml NOT NULL,Comment varchar(1000) NULL,CONSTRAINT PK_foo PRIMARY KEY CLUSTERED (KeyCol)
)
GO

IF OBJECT_ID('dbo.bar') IS NOT NULL DROP PROCEDURE dbo.bar
GO
CREATE PROCEDURE dbo.bar
    @Key char(12),@Value xml,@Comment varchar(1000)
AS
SET NOCOUNT ON
DECLARE @StartTranCount tinyint;
BEGIN TRY
    SELECT @StartTranCount = @@TRANCOUNT;

    IF @StartTranCount = 0 BEGIN TRAN;

    BEGIN TRY
        --SELECT @StartTranCount = 'fish' --generates an error and goes to outer CATCH
        INSERT dbo.foo (KeyCol,ValueCol,Comment) VALUES (@Key,@Value,@Comment);
    END TRY
    BEGIN CATCH
        IF ERROR_NUMBER() = 2627    --PK violation
            UPDATE
                dbo.foo
            SET
                ValueCol = @Value,Comment = @Comment
            WHERE
                KeyCol = @Key;
        ELSE
            RAISERROR ('Tits up',16,1);
    END CATCH

    IF @StartTranCount = 0 COMMIT TRAN;
END TRY
BEGIN CATCH
    IF @StartTranCount = 0 AND XACT_STATE() <> 0 ROLLBACK TRAN;
    RETURN -1
END CATCH
--Without this,we'll send -4 if we hit the UPDATE CATCH block above
--RETURN 0
GO

--please run these **separately**

--Run with RETURN 0 and fish line commented out
DECLARE @rtn int
EXEC @rtn = dbo.bar 'abcdefghijkl','<foobar />','testing'
SELECT @rtn; SELECT * FROM dbo.foo
GO

DECLARE @rtn int
EXEC @rtn = dbo.bar 'abcdefghijkl','<foobar2 />','testing2'
--updated OK but we get @rtn = -4
SELECT @rtn; SELECT * FROM dbo.foo
GO

--uncomment fish line
DECLARE @rtn int
EXEC @rtn = dbo.bar 'abcdefghijkl','testing'
--Hit outer CATCH,@rtn = -1 as expected
SELECT @rtn; SELECT * FROM dbo.foo