On 9/17/14, 7:40 PM, Jan Wieck wrote:
> Exactly. Doing something like
>
> ASSERT (select count(*) from foo
> where fk not in (select pk from bar)) = 0;
>
> is a perfectly fine, arbitrary boolean expression. It will probably work well in a development environment too. And I
amvery sure that it will not scale well once that code gets deployed. And I know how DBAs react to the guaranteed
followingperformance problem. They will disable ALL assert ... or was there some sort of assert class system proposed
thatI missed?
Keep in mind that nothing we come up with will be immune to abuse, and trying to solve what is fundamentally an
educationproblem through technology rarely turns out well.
We're also putting too much weight on the term "assert" here. C-style asserts are generally not nearly as useful in a
databaseas general sanity-checking or error handling, especially if you're trying to use the database to enforce data
sanity.
My wish-list for "asserts" is:
- Works at a SQL level
- Unique/clear way to identify asserts (so you're not guessing where the assert came from)
- Allows for over-riding individual asserts (so if you need to do something you're "not supposed to do" you still have
theprotection of all other asserts)
- Less verbose than IF THEN RAISE END IF
--
Jim C. Nasby, Data Architect jim@nasby.net
512.569.9461 (cell) http://jim.nasby.net