Re: data store

> Vance try:
>
> var data = {data: {
>     identifier : 'id',
>     items : [
>       { id : 'a', label: "Letter A" },
>       { id : 'b', label: "Letter B" },
>       { id : 'c', label: "Letter C" },
>       { id : 'd', label: "Letter D" }
>     ]
>   };
>
> var myNewStore=new dojo.data.ItemFileReadStore(data);
>
> See how that handles it.
>
>
>
> On Dec 13, 2007, at 5:00 PM, Vance Dubberly wrote:
>
> > Dustin,
> >  I really do appreciate the explanation of data stores it is both
> > insightful and honest. Understanding the philosophy of why a thing is
> > architected the way it is goes a long way toward making it work and it
> > sounds like the theory is good, even if the implementation is lacking.
> >
> >  The downside of course is that I'm still left writing my own
> > datastore as at least instantiating dojo.data.ItemFileReadStore with
> > the aforementioned JSON results in a data store with no data. :(
> >
> >  I do think I've a new Tagline for dojo.  "Making the complex,
> > attainable and the simple impossible." :)  ( wasn't the Java credo for
> > a long time? )  I can do things with dojo I never thought possible and
> > yet the simple stuff leaves me totally screwed.
> >
> > Anyway I gave up and just used an old fashioned select box.  Looks
> > like crap but it does the job.
> >
> > Vance
> >
> >
> >
> >
> >
> >
> > On Dec 13, 2007 1:17 PM, Dustin Machi <dmachi@...> wrote:
> >> I agree that lots of work still needs to be done on making use of
> >> stores
> >> easier and more robust.  Right now it can be too difficult to use in
> >> what are simple case. However...
> >>
> >>> Honestly I don't want to use a datastore to do it.  Seems like a
> >>> complete waste of memory and CPU.
> >>
> >> The fact is regardless of whether or not you have to declare a
> >> store or
> >> even if a widget actually uses something called a store, you are
> >> using
> >> one.  This doesn't necessarily mean a dojo.data store, but every
> >> widget
> >> that visualizes some data set must be able to have access to a data
> >> set
> >> that it understands how to access and view and potentially to
> >> manipulate
> >> as well.
> >>
> >> In the previous versions of dojo each widget handled its data on its
> >> own.  This of course led to problems that the particular data set
> >> that
> >> they knew how to manage didn't quite match up with what the user
> >> needed
> >> or wanted.  Or they needed to be retrieved from the server in a lazy
> >> loaded way.  Or lazy loading work, but not in the way that a
> >> particular
> >> dev needed it to work.  dojo.data does nothing more than split that
> >> functionality outside of the widget so stores could be defined in
> >> some
> >> standard way that lets the developers write whatever code they might
> >> like to access their server data, but still provides widgets a common
> >> interface so they don't have to be rewritten, extended or whatever
> >> with
> >> each new use case.
> >>
> >> Now, bugs aside and not withstanding some adjustments that might be
> >> needed to the dojo.data api's themselves, using stores should
> >> ultimately
> >> reduce the number of instances of a piece of data because one store
> >> can
> >> be used by multiple widgets.  It ultimately also requires less widget
> >> code to be written and downloaded.
> >>
> >>> However not using a datastore  does
> >>> not appear to be an option.
> >>
> >> Actually in some cases this is already the case, but as mentioned
> >> above
> >> is only illusory. For example, the combobox widget can take normal
> >> <option> tags as children.  However what happens in reality is that
> >> the
> >> widget will then ingest that data and create the store on its own.
> >> Having capabilities like this available across the full set of
> >> widgets
> >> that use dojo data would go along way towards making some of the
> >> simple
> >> cases simpler.  (
> >>
> >> *on a side note for lurkers: I would say however that widgets that do
> >> this should not automatically dojo.require() the store type they
> >> want to
> >> use as you then have to get that code/store even if you don't want to
> >> use it and that can be expensive.  I would prefer it to just throw an
> >> error if you tried to use a widget in this way and hadn't included an
> >> appropriate store.  It would also be preferable to allow usage like
> >> this
> >> to specify which type of store would be created by default, though
> >> this
> >> might not be practical in some circumstances.  Doing this allow
> >> automatic creation, but if the rest of the app is using a different
> >> store type, it doesn't require that store to be loaded.)
> >>
> >> So baring that, I want to populate a
> >>> datastore with the above object without having to read it from the
> >>> server.  I already have the data it was pulled from the server in a
> >>> much more complex format and is being used for may things. the above
> >>> sample is a derived subset of that data.
> >>>
> >>> what I'd love to do is this:
> >>>
> >>> dijit.form.FiteringSelect.store = pageJSON;
> >>>
> >>
> >> This won't work because that is passing a js object in and the
> >> filtering
> >> select would be expecting that to be a store instance, not a js
> >> object.
> >>
> >>> baring that I'd like to do this:
> >>>
> >>> store = new dojo.data.SomeKindOfStore( pageJSON )
> >>> dijit.form.FilteringSelect.store = store;
> >>>
> >>
> >> This in general is correct, however i think in practical terms that
> >> right now most data using widgets expect to have a store at creation
> >> time.  So your stores would need to be created before the widget was
> >> instantiate.
> >>
> >>> What I don't want to do is go to the server for data I already have.
> >>>
> >> You don't have to go to the server for the data you already have.
> >> ItemFileReadStore takes a set of data, formatted in its special
> >> way, and
> >> makes it available locally.  You could create your stores right at
> >> the
> >> beginning of your app for example (not in addOnLoad() and before the
> >> <body>) and that store could be avialable to anything  you either
> >> markup
> >> or programmatically create later.
> >>
> >>
> >> Dustin
> >>
> >>
> >> _______________________________________________
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> >>
> >
> >
> >
> > --
> > To pretend, I actually do the thing: I have therefore only pretended
> > to pretend.
> >  - Jacques Derrida
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