On 6/30/06, Sjef <manuals-scripts@xxxxxxxxx> wrote:
Thanks, John, I'm not sure I completely get the idea of a pair class. As an question and answer are in the same database tabel I now created a questionDepot class that gets the array from the db, does save and update operations, and for example, sets a flag in the db tabel when a question is accepted for the list.
Hi Sjef, It sounds as if you've got the idea, even if I didn't explain myself well. My point was to *not* create a Question class that maintained an array of questions, which was only _implicitly_ related to a similarly-structured but disparate Answers class. An array of questions sitting beside an array of answers is, in my opinion, not a proper abstraction of the objects you're dealing with. Perhaps it is out of experience that I'm harping on this point, because I've been burned by a similar design before. One of my first OO projects was a weblog, and I had built a Post class, and then for posts with galleries, a separate Gallery class that contained *only* image information for it's parent Post. On it's own, this wasn't all bad, but the big mistake I made was how I handled multiple posts and multiple galleries (like for building out the homepage where I showed 5 recent posts and a thumbnail from each, if they were galleries). Within each Post and Gallery class, I turned the properties into _arrays_. So what originally was a string for the post's title, now became an array of strings for many posts. Likewise for the Gallery class. Arrays of thumbnails became arrays of arrays of thumbnails. I'm sure The List will shudder at this design, but hey, I've learned my lesson. Be-lieve-me. Anyway, the point is, your initial approach was the same (if I read it correctly). You suggested an array of questions, and an array of answers, which would only be implicitly related. Your design started with the concept of many questions, and many answers, but my argument is that, abstractly, you should begin with one question, and one answer. Then think in terms of a question-answer pair that *belong to each other*. And then think of many question-answer pairs. Anyway, I'm sure that by the time you've finished reading this hair-splitting rambling, you've already finished your app and moved on to something else entirely. :) -John W -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
