sql - Can a Check constraint relate to another table?

Question

Let's say I have one table called ProjectTimeSpan (which I haven't, just as an example!) containing the columns StartDate and EndDate.

And that I have another table called SubProjectTimeSpan, also containing columns called StartDate and EndDate, where I would like to set a Check constraint that makes it impossible to set StartDate and EndDate to values "outside" the ProjectTimeSpan.StartDate to ProjectTimeSpan.EndDate

Kind of a Check constraint that knows about another tables values...

Is this possible?

question from:https://stackoverflow.com/questions/3880698/can-a-check-constraint-relate-to-another-table

Answer 1

In response to your comment on GSerg's answer, here's an example check constraint using a function:

alter table YourTable
add constraint chk_CheckFunction
check (dbo.CheckFunction() = 1)

Where you can define the function like:

create function dbo.CheckFunction()
returns int
as begin
    return (select 1)
end

The function is allowed to reference other tables.