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I would like to know what I have to think about in order to download an SQL DB into core data? I am not sure what frameworks I would have to use or if there are any particular requirements when formatting the SQL DB.

Any help, suggestions, links to tutorials would be hugely appreciated.. I have done some searching around and its just hard to make sense of things because I am not sure if what I am looking for is even correct.

HurkNburkS
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3 Answers3

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Im not sure if I understand what you are after, but maybe 2 links would be helpful:

  • an application that lets you load you data to a Sqlite DB from a lots of formats (Excel, xml, ...) is Navicat. It's an easy way of getting data to the DB. As David H mentioned, you could then work with the data without using Core Data via an Sqlite wrapper like FMDB. Then you can access the data with SQL commands.

  • A totally different tutorial is offered by nsscreencst.com: Importing into Core Data is a tutorial that shows how you can import JSON data to Core Data from a web API. This might be related to your use case. Unfortunately the videos there cost $9/month, but IMHO they are doing a terrific job.

(I'm not affiliated with either of the above companies)

Ryan
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brainray
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  • Cool man! thanks a bunch! yea, regarding the second link thats more what I am looking at as the app I am working towards will be centered around offering offline data after an initial download of content... if that makes sense. – HurkNburkS Jul 16 '12 at 22:04
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This is just not possible - even though Core Data can use SQLite for storage there is no import/export. You really have two options:

1) If you have one database you want to use Core Data with within an iOS app, then you can write a really simple Mac App that interacts with your SQL store, and essentially replicates it in Core Data using a Core Data Schema you create based on your SQL database. The advantage of this is that is simpler to test and develop using a mac app. The final Core Data repository can then be used by your iOS app (by including the Core Data Schema with it).

2) Do all the import in your iOS app. This may take longer to develop but you can then dynamically download the SQL database into the phone and use SQLite to read it.

David H
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  • Regarding the 2nd option, could you elaborate on that.. I dont understand the bit where you say (Do all the import in your iOS app).. I dont need exact details just a more detailed explanation, I can do the rest from there, thanks very much for taking the time to answer. – HurkNburkS Jul 15 '12 at 22:19
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    I mean you have to interact with the SQLite store directly - use SQLite directly on iOS. Assuming you know the schema you can read out the values, then create Core Data objects using the schema you defined for it, populate the objects, then save them in Core Data. If you google "iOS SQLite" you will see many pages with code samples of how to read the sql within an iOS app. – David H Jul 16 '12 at 13:42
  • okay cool thanks for that, I have done abit of this before actually so Just need to go over the code again to get it back in my head and I should be sweet. Thanks for the help :) – HurkNburkS Jul 16 '12 at 20:17
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To import your data you have to create NSManagedObjects objects from every single record in your SQLite database. Depending on the complexity of your database model this can be very tricky.

There is a good introduction by Marcus Zarra on how to create NSManagedObjects from JSON: https://stackoverflow.com/a/2363996/480069. This should give you an idea on how to start. As Marcus said be aware of the relationships in your object graph so you don't end up in a loop when having complex relationships.

There are also a lot of good tutorials out there how to serialize NSManagedObjects, so just give Google a try: NSManagedObject serialize.

Community
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Florian Mielke
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