Re: Core Data: Primitive Accessors & Ivar-Backed Properties
Re: Core Data: Primitive Accessors & Ivar-Backed Properties
- Subject: Re: Core Data: Primitive Accessors & Ivar-Backed Properties
- From: Keary Suska <email@hidden>
- Date: Tue, 17 Sep 2013 16:30:09 -0600
On Sep 17, 2013, at 3:58 PM, Sean McBride wrote:
> On Tue, 17 Sep 2013 15:52:05 -0600, Keary Suska said:
>
>> I appreciate the feedback--I am more looking for general feedback by
>> fellow developers about either canonical forms or useful conventions in
>> situations where using an ivar-backed attribute is determined to be
>> useful, rather than to address a specific problem.
>
> An ivar-backed attribute in an NSManagedObject subclass? As opposed to an attribute in the xcdatamodel itself? If so, I have found little use for them, and generally prefer to use transient attributes, since they participate in the "free" undo support. On occasion, I'll use an ivar to get out of undo support actually.
I will say that these questions are specifically related to a software issue, though not about a specific CD issue, but rather software that needs to be able to identify certain possible approaches to coding problems that developers may encounter--just so everyone knows that this isn't just a mental exercise ;-)
Anyway, I haven't had to but the docs do mention that for certain graphics-drawing-intensive applications that performance could be impacted by the constant conversions between scalars and objects, in which case a developer may choose to use an instance variable instead of the default storage (after having determined by scrupulous measurement that such conversions are the issue ;-)
I hadn't considered the undo issue--I guess I just thought undo support was "automagical". If not, are you aware of whether it is implemented at the public or primitive accessor level? None of the doc examples I have seen do any undo handling...
Keary Suska
Esoteritech, Inc.
"Demystifying technology for your home or business"
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