Re: Filtering array returned by an EO's relationship (D2J)
Re: Filtering array returned by an EO's relationship (D2J)
- Subject: Re: Filtering array returned by an EO's relationship (D2J)
- From: email@hidden
- Date: Mon, 03 Nov 2003 14:36:47 CDT
- Priority: 3 (Normal)
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Personally, I think dealing with all that EODatasource stuff is the wrong
path to be going down, unless you are ALREADY using a WODisplayGroup for
your UI, in which case you may already have/need one. I'm not familiar
with WODisplayGroups myself.
But if the question at hand is about filtering relationships in
general... there are simpler ways of executing code to filter the
relationship, that don't involve an EODatasource. You can just use
EOQualifier.filteredArrayWithQualifier to filter an array in-memory.
There's no need to mess around with with WODisplayGroup/EODatasource just
to do an in-memory filter. You can just do it manually yourself in a few
lines of code, without instantiating all those unneccesary objects.
The hard part about filtering a relationship is dealing with caching for
efficiency and invalidating that cache when changes occur. And I don't
_think_ this EODatasource/WODisplayGroup stuff will help with that. But,
like I said, I'm not too familiar with them, so I could be wrong. If they
do help with that, it could be just the thing. But if all you are using
them for is another way of doing
EOQualifier.filteredArrayWithQualifier... it's just a big pain in the
neck for little value.
--Jonathan
On Mon, 3 Nov 2003 13:00:25 -0600 Ricardo Strausz wrote:
> Sorry... I forgot you are dealing with a relation; in such a case, you
> may prefere to use a
> EODetailDataSource instead. You initialize it with:
> ds = EODetailDataSource(theMasterDataSource, theKey);
>
> To get theMasterDataSource, you can use the previous example.
> HIH
> Dino
>
> On lunes, novi 3, 2003, at 11:39 America/Mexico_City, Ricardo Strausz
> wrote:
>
> > Hola Ray!
> > There are, basically, two ways to get an EODatabaseDataSource:
> > * the ease, to ask for to a DisplayGroup (it may be a EODisplayGroup,
> > if you work with EOInterface, or a WODisplayGroup, in a WOApp); simply
> > ds = displayGroup.dataSource();
> > * the pro, to initialize it with
> > ds = EODatabaseDataSource(anEditingContext, anEntityName).
> >
> > After you have one, simply use
> > ds.setFetchSpecification(aFetchSpecification);
> > ds.setAuxiliaryQualifier(aQualifier);
> > anArray = ds.fetchObjects();
> >
> >
> > Read:
> > file:///Developer/Documentation/WebObjects/Reference/API/index.html
> > (recall, EODataSource is defined in EOControl).
> >
> > Suerte!
> > Dino
> >
> >
> > On sabado, novi 1, 2003, at 06:36 America/Mexico_City, Ray Ackland
> > wrote:
> >
> >> Dino,
> >>
> >> Ok. I give up. I have been reading through the API doc's, and
> >> generally going around in circles. I would like to have a go at using
> >> the auxiliary qualifier, but from what I have learnt, I first need to
> >> get hold of the EODatabaseDataSource in question.
> >>
> >> And I believe I can get that from the
> >> WOToManyRelationship.datasource() method. But how do I get the
> >> WOToManyRelationship?
> >>
> >> I see I can get an array of to-many relationships, but this is not
> >> necessary as I already know the key for the relationship I want. But
> >> how do I get that relationship from that key?
> >>
> >> Please point me in the right direction. As usual, the answer will be
> >> obvious once I know what it is.
> >>
> >> Ray.
> >>
> >>> On Wednesday, Oct 29, 2003, at 07:34 Pacific/Auckland, Ricardo
> >>> Strausz
> >>> wrote:
> >>>
> >>>> Did you try dataSource.setAuxiliaryQualifier(aQualifier);
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