小编Hut*_*tch的帖子

在一个存储过程中，我发现如果它成功插入一条记录，它返回 0。如果它在主键违规（被捕获并忽略）时失败，它返回 -4。-4 来自哪里？

下面是存储过程：

ALTER PROCEDURE [dbo].[pSetUserItemLike] 
        @UserID int
        ,@ItemID int
AS
BEGIN
    SET NOCOUNT ON;

    -- for exception handling
    DECLARE @ErrorMessage nvarchar(max)
    DECLARE @ErrorSeverity int
    DECLARE @ErrorState int

    BEGIN TRY
        INSERT dbo.UserItemLikes
        (
            UserID
            ,ItemID
        )
        VALUES
        (
            @UserID
            ,@ItemID
        )
    END TRY
    BEGIN CATCH
        IF ERROR_NUMBER() <> 2627 -- IGNORE PRIMARY KEY VIOLATION
            SELECT 
                @ErrorMessage = ERROR_MESSAGE() + ' Line ' + cast(ERROR_LINE() as nvarchar(5))
                , @ErrorSeverity = ERROR_SEVERITY()
                , @ErrorState = ERROR_STATE();
            RAISERROR (@ErrorMessage, @ErrorSeverity, @ErrorState); …