Re: proposal: plpgsql - Assert statement - Mailing list pgsql-hackers

From Marko Tiikkaja
Subject Re: proposal: plpgsql - Assert statement
Date
Msg-id 5419DB55.5080702@joh.to
Whole thread Raw
In response to Re: proposal: plpgsql - Assert statement  (Peter Eisentraut <peter_e@gmx.net>)
List pgsql-hackers
On 9/17/14, 9:00 PM, Peter Eisentraut wrote:
> On 9/14/14 2:49 PM, Jan Wieck wrote:
>> I don't think it is even a good idea to implement assertions that can
>> query arbitrary data.
>
> In a normal programming language, an assertion is usually a static fault
> in your program.  If the assertion ever fails, you fix your program and
> then it hopefully never happens again.
>
> Assertion that query the state of the database or result row counts are
> pushing that concept quite a bit.  Those are not assertions, those are
> just plain old error handling.

*shrug*  I don't see them as error handling if they're just checking 
conditions which should never happen.

That said, in PL/PgSQL these expressions would likely have to be SQL 
expressions, and then you'd have to go out of your way to implement 
assertions which *can't* query arbitrary data.  And that just seems silly.


.marko



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