HowTo - Constraint for Multi Rows with Same Group ?

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JWOL Hall of Fame Points: 3471 More actions · Answer 1

You could use a trigger that rolls back any inserts that would break your business rule.

Mark Cowne One Orange Chip Points: 26952 More actions · Answer 2

Maybe this?

create function dbo.grpsum(@GroupId int)

returns int

as

begin

return (select sum(ANumber) from dbo.TestTable where GroupId=@GroupId)

end

GO

alter table dbo.TestTable add constraint chkgrp check (dbo.grpsum(GroupId) <= 100)

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angel0in SSC Veteran Points: 294 More actions · Answer 3

Thanks JOWL and MARKS,

JOWL's solution

I think Instead of Trigger will be used.

I have seen Microsfoft's Account Express softare's database. There is not single

Trigger is used. Is microsoft not favour Triggers ?

Marks Solution

Will the performance is an issue with check constraint with function ?

JWOL Hall of Fame Points: 3471 More actions · Answer 4

There are many databases without triggers!

From MSDN: "DML triggers are frequently used for enforcing business rules and data integrity."