Counting instances in Core Data

FROM : Steve Cronin
DATE : Tue Apr 29 18:03:11 2008

Folks;

I want to obtain a count of instances for a specific entity in stored 
in Core Data (SQLite)
In the archive I find this:

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FROM : mmalcolm crawford
DATE : Sun Apr 02 21:21:45 2006
On Apr 2, 2006, at 11:16 AM, Frederick C. Lee wrote:

> How do you count (or determine empty) data from a persistent store 

(table)?

Execute a fetch for the entity in which you're interested, and count 
the returned array.
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My question is: what is the most efficient fetch to pose given that 
every fetch is IO.
A given entity might have a lot of records so an array COULD be an 
unnecessarily large transaction...

Is there a best practice fetch for this 'get a count' purpose?
Steve