如何在 SQL 服务器触发器中进行 IF 检查

Question

我的 table 有以下 Microsoft SQL 服务器触发器：

-- Insert statements for trigger here
DECLARE @AssignmentUID uniqueidentifier;
DECLARE @ResourceUID uniqueidentifier;
DECLARE @ResourceName nvarchar(255);
DECLARE @ResourceClaimsAccount nvarchar(255);
DECLARE @ProjectUID uniqueidentifier;
DECLARE @ProjectName nvarchar(255);
DECLARE @ProjectUrl nvarchar(1000);
DECLARE @TaskUID uniqueidentifier;
DECLARE @TaskName nvarchar(255);
DECLARE @TaskUrl nvarchar(1000);
DECLARE @UserId nvarchar(255);
DECLARE @PWAUrl nvarchar(255);
DECLARE @sql varchar(8000)

SELECT @AssignmentUID = INSERTED.AssignmentUID 
FROM INSERTED;

SELECT        
    @TaskUID = MSP_EpmAssignment_UserView.TaskUID,
    @TaskName = MSP_EpmTask_UserView.TaskName, 
    @ProjectUID = MSP_EpmAssignment_UserView.ProjectUID, 
    @ProjectName = MSP_EpmProject_UserView.ProjectName, 
    @ProjectUrl = MSP_EpmProject_UserView.ProjectWorkspaceInternalHRef, 
    @ResourceUID = MSP_EpmAssignment_UserView.ResourceUID, 
    @ResourceClaimsAccount = MSP_EpmResource_UserView.UserClaimsAccount, 
    @ResourceName = MSP_EpmResource_UserView.ResourceName
FROM
    MSP_EpmAssignment_UserView 
LEFT OUTER JOIN
    MSP_EpmResource_UserView ON MSP_EpmAssignment_UserView.ResourceUID = MSP_EpmResource_UserView.ResourceUID 
LEFT OUTER JOIN
    MSP_EpmProject_UserView ON MSP_EpmAssignment_UserView.ProjectUID = MSP_EpmProject_UserView.ProjectUID 
LEFT OUTER JOIN
    MSP_EpmTask_UserView ON MSP_EpmAssignment_UserView.TaskUID = MSP_EpmTask_UserView.TaskUID
WHERE
    (MSP_EpmAssignment_UserView.AssignmentUID = @AssignmentUID);

INSERT INTO tablename
(ItemTitle, ParentName, ParentUrl, Loginname, SourceId, CreatedAt)
VALUES (@TaskName, @ProjectName, @ProjectUrl, RIGHT(@ResourceClaimsAccount, CHARINDEX('\', REVERSE('\' + @ResourceClaimsAccount)) - 1), 1, GETDATE());

如何在执行 INSERT INTO 语句之前检查@AssignmentUID AND @TaskUID 是否为 NOT NULL？是否还有优化此触发器的潜力？

Answer 1

IF (@AssignmentUID IS NOT NULL AND @TaskUID IS NOT NULL)
BEGIN 
  ...
END

Answer 2

您需要以 set-based 的方式编写触发器，以处理 Inserted table 可能包含多行的事实。

试试这个代码 - 它使用你的核心 SELECT 并对你试图在开始。这将立即处理 Inserted table 中包含的所有行 - 没有循环，没有游标 - 不需要这样混乱的代码！

INSERT INTO tablename (ItemTitle, ParentName, ParentUrl, Loginname, SourceId, CreatedAt)
SELECT        
    MSP_EpmTask_UserView.TaskName, 
    MSP_EpmProject_UserView.ProjectName, 
    MSP_EpmProject_UserView.ProjectWorkspaceInternalHRef, 
    RIGHT(MSP_EpmResource_UserView.UserClaimsAccount, CHARINDEX('\', REVERSE('\' + MSP_EpmResource_UserView.UserClaimsAccount)) - 1,
    1, 
    SYSDATETIME()
FROM
    MSP_EpmAssignment_UserView 
INNER JOIN
    Inserted i ON MSP_EpmAssignment_UserView.AssignmentUID = i.AssignmentUID 
LEFT OUTER JOIN
    MSP_EpmResource_UserView ON MSP_EpmAssignment_UserView.ResourceUID = MSP_EpmResource_UserView.ResourceUID 
LEFT OUTER JOIN
    MSP_EpmProject_UserView ON MSP_EpmAssignment_UserView.ProjectUID = MSP_EpmProject_UserView.ProjectUID 
LEFT OUTER JOIN
    MSP_EpmTask_UserView ON MSP_EpmAssignment_UserView.TaskUID = MSP_EpmTask_UserView.TaskUID

如何在 SQL 服务器触发器中进行 IF 检查

How to do a IF check within a SQL Server trigger

sql

sql-server

sql-server-2008-r2

database-trigger