Core data updating entities
This would include DQL commands like CREATE, INSERT, UPDATE, DELETE, etc.Lets take a look at two different methods to retrieve data using a SELECT statement.When building an i OS application, one thing to consider is a concept called “data persistence.” Data persistence is a method of holding onto data in case the application or device is reset.No one wants to be playing a game or updating their checkbook and lose everything after a reset because a poorly-designed app did not store their information.But it seems what's most likely is that a user will either want to play an individual video, or play a playlist.The request to play all playlists that contain this particular video seems an odd one to me.Even without the video knowing any information about the playlists, your code could still iterate through every playlist asking it whether or not it contained a given video and get the answer to what all playlists the video belongs to.This might be a little time consuming, but I think it's a rare request.
Apple’s Core Data framework, unlike SQLite, takes more of an object-oriented approach to storing user data.
Before we define the exact differences between each method, let’s check out some example code that would be used for each technique.
Comparing the two code samples will give us a better idea of the differences between the two methods.
objects don't really need to know about what playlists they belong to, do they? And when I say this, I mean a request where it's important for this information to be returned near instantly.
You just need an array on each playlist that keeps track of what videos are on its playlist and in what order. It seems to me that the only reason a video would need to know what playlists it belonged to is if you wanted to provide some functionality for a video to quickly find all playlists it belonged to.