Core Data migration problem: "Persistent store migration failed, missing source managed object model
- by John Gallagher
The Background
A Cocoa Non Document Core Data
project with two Managed Object
Models.
Model 1 stays the same. Model
2 has changed, so I want to migrate
the store.
I've created a new version
by Design Data Model Add Model
Version in Xcode.
The difference between versions is a single relationship that's been changed from to a one to many.
I've made my
changes to the model, then saved.
I've made a new Mapping Model that
has the old model as a source and new
model as a destination.
I've ensured
all Mapping Models and Data Models
and are being compiled and all are
copied to the Resource folder of my
app bundle.
I've switched on migrations by
passing in a dictionary with the
NSMigratePersistentStoresAutomaticallyOption
key as [NSNumber
numberWithBool:YES] when adding the
Persistent Store.
Rather than merging
all models in the bundle, I've specified the two
models I want to use (model 1 and the
new version of model 2) and merged
them using modelByMergingModels:
The Problem
No matter what I do to migrate, I get the error message:
"Persistent store migration failed,
missing source managed object model."
What I've Tried
I clean after every single build.
I've tried various combinations of
having only the model I'm migrating
to in Resources, being compiled, or
both.
Since the error message
implies it can't find the source
model for my migration, I've tried
having every version of the model in
both the Resources folder and being
compiled.
I've made sure I'm not
making a really basic error by
switching back to the original
version of my data model. The app
runs fine.
I've deleted the Mapping
Model and the new version of the
model, cleaned, then recreated both.
I've tried making a different change
in the new model - deleting an entity
instead.
I'm at my wits end.
I can't help but think I've made a huge mistake somewhere that I'm not seeing. Any ideas?
