How to store NSDate in Core Data?

Question

When generating Core Data subclasses I check to use primitive data type in Core Data storage.

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Which NSTimeInterval representation should I convert from NSDate? Or it does not matter, just use appropriately when reading / writing the same managed object attribute?

I prefere to use like: mo.creationDate = date.timeIntervalSinceReferenceDate

score 2 · Accepted Answer · answered Apr 17 '15 at 09:59

iOS's reference date counts from : 1 January 2001, GMT.
Unix Time Stamp reference date counts from : Jan 01 1970, UTC

If this is a completely offline app you can use the timeIntervalSinceReferenceDate and store the value directly.

But, if you are going to sync up with a server then generally, it is preferable to send the data to server as a unix time stamp. Because a desktop uses unix time Stamp as default.

So, in the second case you can either choose to save the date directly as a UnixTimeStamp and convert it for local use using a getter in Model Class (refer : @VladZ) or You can save it as iOS's reference date and convert it to UnixTimeStamp each time you send it to server.

score 1 · Answer 2 · answered Apr 17 '15 at 09:45

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Use - timeIntervalSince1970 and save this value in CoreDate

mo.creationDate = [NSNumber numberWithDouble:timeInterval];

answered Apr 17 '15 at 09:45

Vladyslav Zubkov

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why not `timeIntervalSinceReferenceDate`? – János Apr 17 '15 at 09:54
it doesn't matter. You may use timeIntervalSinceReferenceDate – Vladyslav Zubkov Apr 17 '15 at 09:59

score 0 · Answer 3 · edited May 23 '17 at 12:14

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You're adding a time interval, that it's not an object of type NSDate.

Try to add a NSDate with the desired time interval:

Check this out

edited May 23 '17 at 12:14

Community

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answered Apr 17 '15 at 09:34

Pablo A.

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How to store NSDate in Core Data?

3 Answers3