Re: Single Table Inheritance
Re: Single Table Inheritance
- Subject: Re: Single Table Inheritance
- From: Chuck Hill <email@hidden>
- Date: Fri, 07 Oct 2011 08:36:00 -0700
Hi Matteo,
It sounds like something is not right in your model. Check that
- POI is either abstract or has a qualifier (e.g. qualifier type='P')
- the Parent entity of Restaurant and Club is set, check that
- the external (table) name of POI, Restaurant and Club is exactly identical
Chuck
On 2011-10-07, at 7:55 AM, Matteo Centro wrote:
> Hi all,
>
> kind of a stupid question but in my whole career with WO I never used Single Table Inheritance so I'm kind of a newbie here...
>
> I'll try to explain with a small example: I have an entity called PointOfInterest (POI), defined by the main attributes which are name, latitude, longitude, type and with a relationship to a City.
> I then created two subclasses of POI
> Restaurant (with qualifier type='R') and some more attributes
> Club (with qualifier type='C') and some different attributes
> All is mapped in two tables, one for City and one for POI. Everything looked fine in my head...
>
> I find puzzling though that if I ask a City for its POIs I get an array full of duplicates in this example I'm printing out all the POIs for a City:
> POI name: Open POI Class: your.app.logic.Club
> POI name: Jazz Club POI Class: your.app.logic.Club
> POI name: Dal Baffo POI Class: your.app.logic.Restaurant
> POI name: Zushi POI Class: your.app.logic.Restaurant
> POI name: Ristorante POI Class: your.app.logic.Restaurant
> POI name: Dal Baffo POI Class: your.app.logic.Restaurant
> POI name: Zushi POI Class: your.app.logic.Restaurant
> POI name: Open POI Class: your.app.logic.Club
> POI name: Jazz Club POI Class: your.app.logic.Club
> POI name: Generic poi POI Class: your.app.logic.PointOfInterest
> POI name: Ristorante POI Class: your.app.logic.Restaurant
>
> In reality I only have 6 items in my POI table: 3 Restaurants, 2 Clubs and one row with blank type. So I was expecting of getting something like this:
> POI name: Open POI Class: your.app.logic.Club
> POI name: Jazz Club POI Class: your.app.logic.Club
> POI name: Dal Baffo POI Class: your.app.logic.Restaurant
> POI name: Zushi POI Class: your.app.logic.Restaurant
> POI name: Ristorante POI Class: your.app.logic.Restaurant
> POI name: Generic poi POI Class: your.app.logic.PointOfInterest
>
> Maybe I'm approaching the problem in the stupidest way but I'd like to understand a little bit more about what you guys think...
>
> Thanks,
>
>
> Matteo
>
> _______________________________________________
> Do not post admin requests to the list. They will be ignored.
> Webobjects-dev mailing list (email@hidden)
> Help/Unsubscribe/Update your Subscription:
>
> This email sent to email@hidden
--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems.
http://www.global-village.net/products/practical_webobjects
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden