Core Data problems

  • Hi,

    I have kind of a newbie question that I was hoping someone could help
    me with. I'm trying to learn Cocoa/Core Data coming from a different
    background and I got some help from a friend but we have struck out
    and can't figure out what to do next. The idea is very simple. I want
    an array of arrays of cards. The first list should list series (for
    example common kanji, mayan temples, cocoa coding heroes, etc) and the
    second list individual cards. Having selected a card you should be
    able to edit the front and back of that card.

    I have tried to click my way to a solution, so I have stayed away from
    code, and if possible I would prefer a non-code based solution. I'm
    half hoping to do something useful, and half hoping to learn something
    from the ordeal, so "doing the right thing" is high up on my list.

    You can download my project at the URI below (should help if my
    explanation was too bad to follow) and if you have any questions just
    shoot.

    http://www.cenara.com/users/ce01724/FlashCard.zip

    Cheers,
    John Gustafsson
  • On Thu, Feb 21, 2008 at 2:14 PM, John Gustafsson
    <flexo.crashlog...> wrote:
    > I have kind of a newbie question that I was hoping someone could help
    > me with. I'm trying to learn Cocoa/Core Data coming from a different
    > background and I got some help from a friend but we have struck out
    > and can't figure out what to do next. The idea is very simple. I want
    > an array of arrays of cards. The first list should list series (for
    > example common kanji, mayan temples, cocoa coding heroes, etc) and the
    > second list individual cards. Having selected a card you should be
    > able to edit the front and back of that card.

    OK, so you seem to be having a data modeling issue.  First, abandon
    the concept of arrays; Core Data doesn't use them, and you're really
    talking about set theory, so we'll talk about sets.

    So you want to have a set A of subjects.  You also want a mapping F
    from a subject to a set of what sound to me like flashcards.  Elements
    of set A are of type Subject, elements of set F(A) are of type
    Flashcard.  A Subject has a title, and a Flashcard has a front side
    and a back side.

    > From here, it should be very clear how you would model this in the
    Core Data model designer.

    HTH,
    --Kyle Sluder
  • I would strongly recommend leaving Core Data alone until you're more
    familiar with the rest of Cocoa. As the docs say, it makes use of many
    other Cocoa technologies which are almost impossible to learn all at
    once.

    On 21 Feb 2008, at 19:14, John Gustafsson wrote:

    > Hi,
    >
    > I have kind of a newbie question that I was hoping someone could
    > help me with. I'm trying to learn Cocoa/Core Data coming from a
    > different background and I got some help from a friend but we have
    > struck out and can't figure out what to do next. The idea is very
    > simple. I want an array of arrays of cards. The first list should
    > list series (for example common kanji, mayan temples, cocoa coding
    > heroes, etc) and the second list individual cards. Having selected a
    > card you should be able to edit the front and back of that card.
    >
    > I have tried to click my way to a solution, so I have stayed away
    > from code, and if possible I would prefer a non-code based solution.
    > I'm half hoping to do something useful, and half hoping to learn
    > something from the ordeal, so "doing the right thing" is high up on
    > my list.
    >
    > You can download my project at the URI below (should help if my
    > explanation was too bad to follow) and if you have any questions
    > just shoot.
    >
    > http://www.cenara.com/users/ce01724/FlashCard.zip
    >
    > Cheers,
    > John Gustafsson
  • I was kind of hoping to just get this simple thing going, and then I
    could learn more cocoa from there. I'm quite familiar with frameworks
    on the whole, but I need kind of an "in". I never could learn as well
    from reading as from doing:) I was kind of hoping that this would be
    quite a simple core data app after all, so that I didn't have to
    venture further into core data for a while.

    Anyone who could give me a hint to why the second list view isn't
    working? Seems like we got the data model working quite well, we just
    can't connect it :( The app really should be dead simple to fix for
    someone in the know.

    Cheers,
    John

    On 21 Feb, 2008, at 21:03, Mike Abdullah wrote:

    > I would strongly recommend leaving Core Data alone until you're more
    > familiar with the rest of Cocoa. As the docs say, it makes use of
    > many other Cocoa technologies which are almost impossible to learn
    > all at once.
    >
    > On 21 Feb 2008, at 19:14, John Gustafsson wrote:
    >
    >> Hi,
    >>
    >> I have kind of a newbie question that I was hoping someone could
    >> help me with. I'm trying to learn Cocoa/Core Data coming from a
    >> different background and I got some help from a friend but we have
    >> struck out and can't figure out what to do next. The idea is very
    >> simple. I want an array of arrays of cards. The first list should
    >> list series (for example common kanji, mayan temples, cocoa coding
    >> heroes, etc) and the second list individual cards. Having selected
    >> a card you should be able to edit the front and back of that card.
    >>
    >> I have tried to click my way to a solution, so I have stayed away
    >> from code, and if possible I would prefer a non-code based
    >> solution. I'm half hoping to do something useful, and half hoping
    >> to learn something from the ordeal, so "doing the right thing" is
    >> high up on my list.
    >>
    >> You can download my project at the URI below (should help if my
    >> explanation was too bad to follow) and if you have any questions
    >> just shoot.
    >>
    >> http://www.cenara.com/users/ce01724/FlashCard.zip
    >>
    >> Cheers,
    >> John Gustafsson
    >