Re: Is it possible to create a CHECK constraint for my use case?

Gnanakumar, 31.01.2012 09:11:
> Hi,
>
> Our Production server is running PostgreSQL v8.2.22 on CentOS5.2.

You know that 8.2 is "end-of-live"?
http://www.postgresql.org/support/versioning/

> There are 2 columns in the table: "managertype" numeric(1) and "managerid"
> numeric(10). "managertype" accepts only 2 valid values, either '1' or '2'.
>
> managertype | managerid
> ---------------------------------
> 1 | null values NOT allowed
> 2 | null values allowed
> ---------------------------------
>
> We want to enable a CHECK constraint based on 2 columns data in the table in
> such a way that if "managertype" is 1, then null values are not allowed in
> "managerid" column. In other words, I want to create a CHECK constraint
> something like this: IF (managertype = 1) THEN managerid IS NOT NULL.
>
> Is it possible to create a CHECK constraint for my use case explained above?

Something like this:

check ( (managertype = 2) or (managertype = 1 and managerid is not null) )

Not sure if the condition (managertype = 2) is actually needed, if the managertype is already constrained to 1/2 but I can't test it right now.

Thomas