Question

Is there a way to enforce constraint checking in MSSQL only when inserting new rows? I.e. allow the constraints to be violated when removing/updating rows?

Update: I mean FK constraint.

Answer 1

You could create an INSERT TRIGGER that checks that the conditions are met. That way all updates will go straight through.

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