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Apple ResearchKit: how to extract information from ORKResult? First time programmer

I'm working on a simple ResearchKit app that has 20 survey questions, or ORKSteps. How do I get the answers from a participant who submits the survey into a database?

My research has found ORKESerializer and SQLite as potential parts of the solution. I'm missing a big picture view of how these things can be integrated into a working solution.

Starting without knowledge of databases or data transfer from Swift, so any basic information would be very helpful.

  1. How do I extract data from ORKResult using Swift?
  2. Where do I extract the data to? Or, what's the standard type of database for a small survey?
Solution

  • ResearchKit doesn't have any out-of-the-box solution for storing your results. Generally, it's the task of the developer to go through the ORKResult hierarchy and either persist the processed results for later access or send them to a remote server.

    You have several options here:

    • Use NSCoding to store the vanilla ORKTaskResult (with their ORKResult children). This way you can recreate the whole ORKTaskResult hierarchy at later time to inspect or process it.

    • Use ORKESerializer (as you guessed) to serialize ORKResults into the JSON format. ORKESerializer is currently included as part of ORKTest's unit tests, and it's not documented very well. It's possible that it will be moved to ResearchKit proper in the future, but it's completely usable right now. The JSON format is particularly useful if you want to send your results to any remote server of your own.

    • You can manually iterate through ORKResults and convert them into objects that are suitable for storing, or into database records. As you said, you could persist them using SQLite; or other database of your choice; or Core Data.

    To sum up, there's no recommended or standard method for persisting results, it depends on your needs.

    You can also have a look at the official open sourced RK apps. I think they make use of the AppCore library (which sits on top of the ResearchKit) to store the task results (and also use the Sage Bridge to send the results to Sage's servers). But that may be overboard if your needs are simpler.

    I suggest that you run the sample ORKCatalog app and then inspect the ORKTaskResult hierarchy (you can do that within the app itself). You'll get an idea of how the result hierarchy looks.