I have an app, using Core Data with a SQLite store.
At some point I'd like to remove all objects for a few entities. There may be close to a thousand objects.
From what I can tell via google and the official docs, the only way to delete objects is to [managedObjectContext deleteObject:(Entity *)] for every object. But this means that I must first fetch all objects.
The data store is just sqlite, is there no way to simply pass a TRUNCATE TABLE ZENTITY; to it?
The issue is that CoreData isn't just a SQLite wrapper. It's an object graph management solution and it stores cached versions of your object in memory in addition to other stuff. As far as I know to remove all instances of a given managed object you'll have to fetch them and then delete each. This isn't to say that this functionality shouldn't exist, because it probably should.
Have you actually tried it and found it to be a performance issue? If so, then you could provide some information showing that, and more importantly file a bug report on it. If not, then why are you bothering to ask?
It's not as simple as doing a TRUNCATE TABLE ZENTITY; since Core Data must also apply the delete rule for each object (among other actions), which means doing a fetch. So they may as well let you make the fetch and then pass the results into the context one-by-one.
If you relate your objects to a parent entity simply delete the parent. If your parents delete rule is set to 'cascade' all of those (1k) children will be removed as well.
John