Re: Core data design related question
Re: Core data design related question
- Subject: Re: Core data design related question
- From: Marc Rink <email@hidden>
- Date: Thu, 22 Oct 2009 21:46:27 +0200
Hey Florijan!
Thanks for your guidance: TBQH, i already came along your described
way: started out with the obvious "Hello World" stuff, playing around
with IB and different techniques to deal with object's etc. Eg i
already had a working version of a window with a popup box feeded from
a MySQL table content (i will need this later on), i strayed accross
Core Graphics to load a PNG, cut it into tiles and draw the tiles in a
scroll view, etc.
I know that core data might be overkill for just storing the
configuration info, but i need core data along the way (only with
transient properties) so i figured it may be ok to handle everything
in there.
Your hint with just creating a object controller in ConfigView did the
trick! :) Sometimes you can't see the forest because of lots of trees
standing in your view...
This means i need the ObjectController in every view i want to have
access to the connection parameters.
However, i am now troubling around: I set the value Binding of the
Textfield to the object Controllers.selection.<value> in IB, however
i wont see the defaultvalue i have set in the model designer in Xcode.
I already fiddled around with "Enabled" and "editable" bindings, but i
didnt get it to work...?
Anyone able to point me in the right direction?
thanks
Marc
Am 22.10.2009 um 16:10 schrieb Stamenkovic Florijan:
Hi Marc,
On Oct 20, 2009, at 16:11, Marc Rink wrote:
Heyas,
I am quite new to Objective-C (and to some extend to OO concepts as
well), so please be gentle with me :)
I have a core data based document application that purpose is to
access a mysql database (i am using the MCP Kit).
The documents in my context are Views that contain different
aspects of the database (small portions consisting of some tables
related to each other).
One document contains the connection parameters for the database.
I am switching the views according to Aaron Hillegass' example
using a view controller (the downloadable examples are http://www.bignerdranch.com/solutions/Cocoa-3rd.tgz)
.
I want to achive the following:
Upon application start the first view "ConfigViewController" is
shown. It contains all connection related parameters (such as host,
port, user, password and database) and a "Connect" button.
Upon clicking the "Connect" button, the connection to the database
is established. The result is a connection object, that i wanted to
pass around the different Views.
First approach was to pass the resulting connection to the
superclass of the view's (all my view's are derived from a custom
superclass which extends NSViewController). For reasons i dont
know, i didnt get this to work. The resulting object was invalid
(nil) in the other view's.
Second approch (and better one imho) is to add a core data entity
"DBConfiguration" holding all connection parameters (persistent, so
you dont have to enter the stuff every time) and a transient
property for the connection object (of type undefined).
I added a Object Controller to my documents xib file, set the mode
to "Entity" and the entity name to "DBConfiguration".
My Problem now is: The view containing the textfields and the
"connect" button are in a different xib file (ConfigView.xib, whose
Files Owner is of Type "ConfigViewController". I dont know how to
bind the ConfigView's text fields to the Object Controller in
MyDocument.xib.
OK, this was a lot of info. What is your actual problem? Can't you
simply make another object controller for DBConfig in ConfigView.xib?
Also note that CoreData is probably not the right solution for
storing your connection info. From what you say the user defaults
system seems much more appropriate.
I am still new to the different frameworks and unsure about whether
my design is acceptable or if i am on a completely wrong way.
When taking on so much at once (as you claim to be inexperienced),
it is almost guaranteed you are not doing things the right way.
Still, your app seems quite complex and it does not make sense
trying to explain it all when looking for a solution for a
reasonably small problem. I am sure you'd get more answers if you
put the question to the point.
Also, if you are really new to all of this stuff, this sounds like a
big first step. Too big. Start with small, isolated functionalities
and practice.
F
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