Re: IS-A relationships in core data
Re: IS-A relationships in core data
- Subject: Re: IS-A relationships in core data
- From: mmalc crawford <email@hidden>
- Date: Tue, 20 Nov 2007 10:16:20 -0800
On Nov 20, 2007, at 9:50 AM, Daniel Child wrote:
Another question is that, while Core Data can store data in XML
format, can it really handle complex hierarchical structures like
those in dictionaries, where there may be any number of parts of
speech indicators, meanings, associated explanations or sample
sentences, etc?
If you can express the data in terms of a schema and an object graph,
then there should be no reason why it cannot be represented using Core
Data.
So one source of my confusion stems from the fact that Core Data can
store data in SQLite format, but does not really work like SQL at all.
Indeed, to reiterate part of the article I mentioned in the first
reply (hmm, which should have had an opening sentence, "I'll address
various points in separate replies to keep them focused."):
"If you're trying to make Core Data act like a database, you're doing
the wrong thing -- see <http://developer.apple.com/documentation/Cocoa/Conceptual/CoreData/Articles/cdBasics.html
>."
"Core Data provides an infrastructure for object graph management and
persistence." In some respects it does act like a RDBMS, in many
others it emphatically does not -- for example, you do fetch data
using a query term, but you don't have access to primary keys, join
tables used to establish many-to-many relationships are hidden from you.
mmalc
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