Take a look at the source project on Git Hub and build the source yourself to see how it all comes together.
This post and the source code for it have now been updated to Swift 3 and Xcode 8.
Experience with RDBMSs (in some other lifetime) reminded me that performing the right query could be far more efficient and so the search was on to find an appropriate optimization.
In the mean time I had resorted to doing a background fetch (on a background context) and calculation that loaded an activity spinner to let the user know that the fetch/calculation was occurring, but I hated doing that to my users–and I guarantee they hated that experience.
I think that if it helps you understand what is going on behind the scenes better, then go for it.
You do have to remember some key differences that can bite you like the need to fetch before updating or deleting, for example.
Once I found a way to properly do an aggregate fetch (as demonstrated in this post), I didn’t even have to perform it in the background.
Census Bureau- Reports at Least 350 Languages Spoken in U. request.properties To Fetch = expression Descriptions data source on the master side of our split view controller.Here is what our app looks like with the data fully populated (click to enlarge): You can see that we’ve built out the detail side of the split view controller to also display a table view that contains a list of all of the products for the selected product line.When it comes to aggregating data, or in more simple database-y terms, data you want to group by, it’s not immediately obvious in Core Data how to go about what you need using a fetch–to the point where some have wondered if it was even possible.It would be nice if there were some mechanism or even syntactic sugar around it that would make it a little more database-y since that makes it easier to grasp, but I think that if we start from a database SQL query and work our way back to a Core Data fetch that uses , it will make a whole lot more sense.That is a nice optimization that makes for happier users.