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Re: Fetch Spec Question
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Re: Fetch Spec Question


  • Subject: Re: Fetch Spec Question
  • From: Jonathan Rochkind <email@hidden>
  • Date: Thu, 22 Jan 2004 10:40:39 -0600

At 9:21 AM -0500 1/22/04, Dana Kashubeck wrote:
Jonathan Rochkind wrote:

An EOFetchSpecification, passed to someEditingContext.objectsWithFetchSpecification() will _always_ go to the database. There will always be a round trip to the db triggered.

Won't the fetch specification still get the objects out of memory unless you set refreshesRefetchedObjects to YES? My understanding is that this is the only way to force it to fetch from the database.

A trip to the database will occur in either case. SQL will get generated. Certain rows will be returned by the db, and EOs corresponding to those rows will be included in the NSArray returned. _Which_ EOs are returned depends on what the database returns. However, you are right, that the _attributes_, the actual _values_ of those EOs, may come from memory. EOF will pay attention to _which_ rows are returned (ie, the primary keys), but may ignore the other non-pk values of those rows, taking those values from memory instead.


As others have posted, there are numerous other customizations and configurations you can perform to change this situation somewhat, there are a bunch of factors that can effect it (settings on the entity like 'read-only' for instance).

--Jonathan



--
-------------------------------------
Dana Kashubeck
Systems Manager
Riemer Reporting Service Inc.
http://www.riemer.com

Phone: 440-835-2477 x. 125
Fax: 440-835-4594
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References: 
 >Fetch Spec Question (From: james cicenia <email@hidden>)
 >Re: Fetch Spec Question (From: Jonathan Rochkind <email@hidden>)
 >Re: Fetch Spec Question (From: Dana Kashubeck <email@hidden>)

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