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iOS

Posted by Joseph Lau
Joseph Lau
5,420 Points

Difference Between Managed Object "Model" vs "Context"

What's the difference between Managed Object Model and Managed Object Context in Core Data?

3 Answers

Michael Vilabrera
PLUS
Michael Vilabrera
Courses Plus Student 11,252 Points
Michael Vilabrera
Michael Vilabrera
Courses Plus Student 11,252 Points

Managed Object Context is the "scrap paper" for any object you have. You may have several of these. Managed Object Model is the data model where your entities are kept. You only get one of these.

Joseph Lau
Joseph Lau
5,420 Points
Joseph Lau
Joseph Lau
5,420 Points

Where is this scrap paper?

Michael Vilabrera
Michael Vilabrera
Courses Plus Student 11,252 Points

haha think of Managed Object Context as clay before molding. We can modify it or toss it before saving (a literal setting in stone, if you will)

Joseph Lau
Joseph Lau
5,420 Points
Joseph Lau
Joseph Lau
5,420 Points

so using this analogy, where does the manage object model come to play?

Michael Vilabrera
Michael Vilabrera
Courses Plus Student 11,252 Points

The Managed Object Model contains information about the entities. I like to think of it as the cookie cutter, although that may not be the best analogy. I asked someone and he told me that the MOM are just objects (book, store, car) which there can be many of which are unique but also have similar properties. I'm attaching links from Apple if you are still confused.

Managed Object Model https://developer.apple.com/library/prerelease/mac/documentation/Cocoa/Conceptual/CoreData/Articles/cdUsingMOM.html

Managed Object Context https://developer.apple.com/library/ios/documentation/DataManagement/Devpedia-CoreData/managedObjectContext.html