On Thursday, December 28, 2017, David A. Cobb <david(dot)a(dot)cobb(dot)1943(at)gmail(dot)com>
wrote:
>
> The values should be fixed as part of the definition process.
>
You can make it difficult to alter the table contents but not impossible -
and I'd lean toward a table rather than a check constraint.
Grants and triggers are your most direct tools of choice here.
David J.