RE: [CFCDev] New to OO, question about inheritance and DAO's

[Nando]

Boson, welcome. I like your name.   First thing to think about is what type of relationships you want to use to model Page and Lecture and Activity. I'm not sure how much studying you've done on the difference between inheritance and compostion. To keep it short and to the point, i highly doubt that Lecture and Activity should extend Page. On a high level, conceptually, it makes more sense to me that a Page can be composed of information about a Lecture or an Activity - maybe both - you might have several Activities or Lectures on a Page.   But to get us on the ground with a functioning web application your model might turn out differently than you first conceive of it on a high level. Let's say you print out a mock up of one of these pages and your 6 year old child (i'm very liberally assuming you have a 6 year old child) started pointing to various parts of the page.   What's that?   That's a Banner   What's a banner?   Well, it's just an Image actually.   What's that?   Oh, that's the Navigation   What's that?   That's the Content   What's Content   Well, on a web Page, Content is made of Text and Images   How does it get there?   Well, when i build a Page, i need to arrange the Content in a Layout.   What's a Layout?   Well, a Layout is ... well, it's really just a group of Containers that I put the Content in.   So what i'm saying with the little story there is that while on a higher conceptual level, you might be at first thinking of a model in terms of Pages, Lectures and Activities, it might be useful to look at it from another perspective at the same time, more a nuts and bolts thing of what is a page composed of when the application actually has to build it. You might wind up with Lectures and Activities in your model, but i think things will fall into place easier for you if you include the nuts and bolts stuff ... if what you're actually thinking of doing with the app is to build web pages.   I'd actually suggest printing out a mockups of your pages, pointing at various parts and keep asking yourself "What's that?" - you'll have a first sketch of your model sussed out pretty quickly that way.   ciao, Nando -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Boson Au Sent: Wednesday, November 02, 2005 11:11 PM To: CFCDev@cfczone.org Subject: [CFCDev] New to OO, question about inheritance and DAO's Hi, I’m building my first OO app and I have a question regarding inherited classes and how they correspond to DAO’s.   Here’s my situation:   I’m building a pageManager application that basically stores different types of “pages” of a course. Currently there are two types of pages: Lecture and Activity.   This is how they break down:   A generic page has pageID              INT pageTitle           string courseID           INT pageLanguage   INT pageDescription string pageType          INT   a Lecture is a child of page with lectureID           INT lectureNumber   INT faculty(s)           Array(1) of faculty objects   and Activity is a child of Page with activityID           INT activityContent   text       I’m really confused as to how to design DAO’s for this.  I want to be able to have a pageManager cfc that takes a pageID as a field and returns either a lecture or activity object.     Do I build multiple DAO’s that corresponds to each different subclass (ie: a lectureDAO and an activityDAO)?  Do I build one pageDAO that has in its CRUD logic that handles what databases to work with based on the class?     Boson Au Web Content Developer Center for Teaching and Learning with Technology Johns Hopkins University Bloomberg School of Health [EMAIL PROTECTED] 410-223-1671   ---------------------------------------------------------- You are subscribed to cfcdev. To unsubscribe, send an email to cfcdev@cfczone.org with the words 'unsubscribe cfcdev' as the subject of the email. CFCDev is run by CFCZone (www.cfczone.org) and supported by CFXHosting (www.cfxhosting.com). An archive of the CFCDev list is available at www.mail-archive.com/cfcdev@cfczone.org ---------------------------------------------------------- You are subscribed to cfcdev. To unsubscribe, send an email to cfcdev@cfczone.org with the words 'unsubscribe cfcdev' as the subject of the email. CFCDev is run by CFCZone (www.cfczone.org) and supported by CFXHosting (www.cfxhosting.com). An archive of the CFCDev list is available at www.mail-archive.com/cfcdev@cfczone.org