仅在MSSQL中插入行时强制执行约束检查？

Question

有没有办法在插入新行时在MSSQL中强制执行约束检查？即在删除/更新行时是否允许违反约束？

更新:我的意思是FK约束.

Answer 1

您可以创建一个INSERT TRIGGER来检查是否满足条件.这样所有更新都将直接通过.

CREATE TRIGGER employee_insupd
ON employee
FOR INSERT
AS
/* Get the range of level for this job type from the jobs table. */
DECLARE @min_lvl tinyint,
   @max_lvl tinyint,
   @emp_lvl tinyint,
   @job_id smallint
SELECT @min_lvl = min_lvl, 
   @max_lvl = max_lvl, 
   @emp_lvl = i.job_lvl,
   @job_id = i.job_id
FROM employee e INNER JOIN inserted i ON e.emp_id = i.emp_id 
   JOIN jobs j ON j.job_id = i.job_id
IF (@job_id = 1) and (@emp_lvl <> 10) 
BEGIN
   RAISERROR ('Job id 1 expects the default level of 10.', 16, 1)
   ROLLBACK TRANSACTION
END
ELSE
IF NOT (@emp_lvl BETWEEN @min_lvl AND @max_lvl)
BEGIN
   RAISERROR ('The level for job_id:%d should be between %d and %d.',
      16, 1, @job_id, @min_lvl, @max_lvl)
   ROLLBACK TRANSACTION
END