Re: Core Data: How best to create a data model for tracking changes to related objects?
Re: Core Data: How best to create a data model for tracking changes to related objects?
- Subject: Re: Core Data: How best to create a data model for tracking changes to related objects?
- From: René v Amerongen <email@hidden>
- Date: Mon, 12 Feb 2007 09:47:20 +0100
Op 12-feb-2007, om 7:19 heeft Steve Weller het volgende geschreven:
On Feb 11, 2007, at 9:44 PM, Scott Stevenson wrote:
On Feb 11, 2007, at 8:37 PM, Steve Weller wrote:
2. If I create an abstract entity called TrackedItem with a name
and a UUID and make that the parent of Files and Folders then I
can remove the name and UUID from them, and Transaction just has
a to-many relationship with Tracked Item. This seems much simpler.
I agree. This is easier for a number of reasons. There's
ultimately little that separates folders and files, particularly
if you consider file packages, which are folders that just appear
to be single files to the user.
Assuming I go this way, how do I distinguish between files and
folders that are returned as query on a TrackedItem for, say a
range of dates? Is it necessary to have a flag in the abstract
entity that says "I am a folder" or "I am a file" so that my query
is possible, or is there a way that does not involve filtering the
TrackedItems a second time?
I know nothing about UUID
Depends on your particular situation.
Normally when you can calculate a flag ( f.e file/folder difference),
use that, if not add a flag.
Then check what kind of flag you need, a boolean or using an integer,
fast or a small file. How big will each of those flags be in binary
compared with a xml file?
But then again, like Scott Stevenson wrote, 10.000 items is nothing
worry about.
HTH
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