FetchRequest: Select distinct and non-distinct properties

Xintare · 01-19-2011, 12:07 PM

Hi there,

I have two Core Data entities for my sqlite-database. One for locations:

Locations

Code:

   
|	locationID	|	locationName	|	countryCode	|
|	292239		|	Berlin		|	de		|
|	291074		|	Paris 		|	fr		|
|	295522		|	Orlando		|	us		|
|	292345		|	Tokyo		|	jp		|

There is also a one-to-many relationship with a "AlternateName" entity:

AlternateName:

Code:

    |  searchName       |    displayName
    |     Berlino       |      Berlinó      
    |     Berlina       |      Berlinà
    |     capital       |      capitall
    |     Parisa        |      Parìsa
    |     Pariso        |      Paríso
    |     Orlandola     |      Orlandolá
    |     Orlandolo     |      Orlandolò

The "AlternateName" entity has a backwards one-to-one relationship to a "Location".

My predicate takes a searchTerm and looks at the "searchName" for every "AlternateName". I would like to get only ONE "AlternateName" per location.

I can take my fetchRequest and set it to returnsDistinctResults only. Then I would have to include "location" (the backwards relation objectID) into my propertiesToFetch. Also, the resultType will have to be a NSDictionary in order for the distinct results to work.

My problem is: Having this configuration, how do I read the "displayName" of my results? I can't include it in the propertiesToFetch, because then, I will get ALL the "alternateNames" for a location. If distinctResults wouldn't limit you to a NSDictionaryResultType, things would be easier.

I hope I made myself clear...
Any ideas? The data could be preprocessed again. Thanks in advance!