How to fetch the last entry of each entity in core data iOS

Question

I am making a chat application in iOS. I saved the last conversation of every friend. My core data entity has 3 fields - jID, message and timestamp. I don't set indexing on any field.I just want to fetch the last message of each jID. So,please help me and also tell me whether to set indexing on any field so that fetching process would be appropriate.

score 1 · Accepted Answer · edited Apr 23 '13 at 18:36

1

You could also add a one-to-one relationship between your entity and the last conversation (you will have to maintain it yourself, if you reveal your model I might be able to be a bit more specific).

A property that is used to filter data, and is used to access elements by, should probably be indexed.

This mean that you probably would want your jID and timestamp indexed.

edited Apr 23 '13 at 18:36

Monolo

18,205
17
69
103

answered Apr 23 '13 at 18:26

Dan Shelly

5,991
2
22
26

score 0 · Answer 2 · answered Apr 23 '13 at 14:41

If you want to fetch the last object, you'll need to have them ordered. Timestamp would be fine for this. And if you want to fetch the last object, reverse the ordering and just fetch the first instead.

If you want to use jID, the ids will have to be in some kind of order.

How to fetch the last entry of each entity in core data iOS

2 Answers2