[Dbix-class] Lazy Columns
rabbit+dbic at rabbit.us
Tue May 11 16:40:50 GMT 2010
Bill Moseley wrote:
> On Tue, May 11, 2010 at 8:02 AM, Peter Rabbitson <rabbit+dbic at rabbit.us
> <mailto:rabbit%2Bdbic at rabbit.us>> wrote:
> > I didn't see this as a bug in Ordered. Ordered asked for the column
> > data and got an undefined value and assumed it was null. Seemed more
> > like an example of why might be good for DBIC to throw an
> exception if a
> > column is accessed w/o being fetched.
> It may or may not be - this is beyond the point. The public API from
> day one
> has been "you get all columns by default" and "every accessor always
> But part of the API is also passing in "columns", correct?
> If you alter the selector, and then do not check that you are asking for
> something that *you* did not bring back from the db - you get to
> keep the
> pieces. In this case Ordered is clearly misusing the API, thus the
> is with Ordered, and it will be fixed sooner or later (sooner if we
> get a
> test case contribution).
> Guess I still don't follow. I've *given* Ordered an item I fetched w/o
> including the position column. It's really my fault for doing that.
> Ordered has no way of knowing that the object passed to it didn't fetch
> the column it needs, right? Is there currently a way to inspect a row
> object and determine what columns were fetched from the store?
This means you didn't even read the original thread, which clearly mentioned
So yes, if a component *relies* on some data being available, it *must*
ensure it is available (as shown above).
> ^^ nowhere do you inform DBIC that there is in fact a unique constraint
> on the source/table. The moment you do the appropriate
> the SQL will magically change to being correct :)
> Well, that makes sense. Any exactly why I posted the full example.
> Although now the database takes more of a beating... ;)
Read the comment at lines 791-794, I need a volunteer to make me a list of databases
which can do that without stepping on its own toes. Then we can make exceptions based
on underlying storage.
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