I received the source for an application from a guy to make a few changes in the app. The data model version was, say, App3. I had to add about 3-4 more data model versions in the process. So the active model version when I sent him was App7
I built the project (it was running properly on my mac)
I sent him the zip and when he ran, he got the error "Can't find model for source store"
I had him create the latest data model again, based on the data model App3 and make it the same as App7 and set it as the current version.
He still has the error and I can't figure out why? Are the intermediate data model version causing issues? Is it required to delete the sqlite file in the application support->iphone simulator folder? I am all over the place with this. Please help!
You need to have both model files and have some sort of versioning in place. The new model that you made will no longer work with his data file unless you specify to Core Data that you want it to update the data.
Versioning isn't that easy, but if your changes are small enough, you might be able to get away with automatic versioning. Read the guide and see:
http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CoreDataVersioning/Articles/Introduction.html
In my understanding, it will. But really that is not the thing to do if ultimately the versioning is going to happen on existing live apps too.
For the light-weight migration to work, you need to send him all the intermediate versions of the model as well since the migration takes place stage by stage through all versions.
And you have to make sure that you have made no modification (even accidentally) to the base version App3.
Related
I actually have a project with 6 core data models like V1 to V6,all are on app stores now when I am trying to update app from one of the older version (core data modelV3) to the current version it crashes (schema mismatch)
when investigated actually V3 model version is different between two project version from older V3 Model to current Model V3.
as in V3 version i added new entity and did not do LightWeight migration(forgot to do it), now is it any way I can allow users to upgrade this older app version with V3 model to the current app version like by solving this (Missing migration issue)
Please suggest any way to add a missing migration model if possible to provide smith upgradtion of the older app version to the current app version.
addPersistentStore should automatically perform necessary lightweight migration. Check if that code is reachable in all your application starting paths.
For that to happen, you need to supply correct set of options, as below:
do {
let options = [ NSInferMappingModelAutomaticallyOption : true,
NSMigratePersistentStoresAutomaticallyOption : true]
try persistentStoreCoordinator.addPersistentStore(ofType: NSSQLiteStoreType,
configurationName: nil,
at: persistentStoreURL,
options: options)
} catch {
fatalError("Problem loading Persistent Store")
}
Please also make sure your main xcdatamodel file points to latest version of your datamodel. Also note that following picture is taken after selecting your latest version xcdatamodel file (yourdatamodel 2.xcdatamodel), not the root xcdatamodel file (yourdatamodel.xcdatamodel).
A word of caution:
Reconsider: do you really need something beyond lightweight? In most situations, lightweight should resolve your problems.
You can get away with lightweight by adding more fields and stop using older fields in your code, thus making the task easier for Core Data. For rows relying on older fields, simply run some insert/update/delete operation if core data model version change is detected.
In order to check where lightweight fails, you can consider enabling following XCode argument:
-com.apple.CoreData.MigrationDebug 1
If lightweight isn't capable of fully migrating your model (such as you have renamed your entities, or data types have changed, which is very unrealistic and you should really reconsider your design if you are doing this), then you can consider this somewhat complex solution:
add persistent store with older model version and back up existing rows in some external file (non core data)
deleting the old persistent store and recreate it using addPersistentStore + newer model version
use newer persistent store to insert backed up data
If all else fails, then consider mapping model alternative. Refer to this article for more details.
I'm trying to overcome the following issue...
I have a MariaDB database that is used for an IOS application.
I'm about to release a new version to the apple store that uses a different version of the schema of the database. means all achievement related tables are modified.
can liquibase be used to configure the changes and allow selected users to connect and work with the schema as if the old schema version is configured, and to actually make the actual changes to the new schema?
before I release the application I need to provide apple with a test version so they will confirm it. so I want users that are connected from apple to see the new achievements features and to work with the new schema while regular users to still be able to user to previous version of the application and to work with the old schema that behind the scenes will actually update the database according to the new schema.
I hope I explained myself properly.
can Liquibase do that ? or it's just like a git for db changes ?
thank you! :)
So I'm working on a project which has been published to users. Before I put my hand on this project, this project has an 1.0 and an 2.0 version, v2.0 modified the data model of core data, but the one who did this didn't add a new version to data model.
So when user upgrade from v1.0 to v2.0, it will crash.
My problem is now I'm deploying v3.0, how do I modify my xcdatamodel so that user with v1.0 and v2.0 can both upgrade to v3.0 without problem?
Get the V1 model and add a new version to it that is identical to v2 and then add another V3 model to that so that you end up with a model that has all three versions. That way you should be able to use lightweight migration from either of the previous versions, assuming that your model changes will in fact support lightweight migration. If not then do a manual migration as suggested by #Mundi. You can recover the V1 model from the V1 app bundle if you no longer have the source code but you do need a copy of the V1 app bundle to do so. You might have to google for how to do this or let me know and I will hunt around as I will have it documented somewhere... Hope this helps.
The only feasible solution that comes to mind seems to be to include two data models in the bundle. (Essentially, the versioning system does something similar.)
Read the data with the first model, then "manually" copy it to the data store of the second model (modifying it as necessary). From then on, only use the second model (which should be versioned for future changes).
I would block the UI and put up a message like "migrating your data" to make sure no user interaction interferes with this process.
In our existing app, we have many different version of xcdatamodel:
+ TheApp.xcdatamodel
TheApp.1.0.xcdatamodel
TheApp.1.1.xcdatamodel
TheApp.2.0.xcdatamodel
...
We know that the traditional way of doing database migration testing is what have been proposed in this question: How to Test Core Data Migration With an App Already in the App Store? In short, it works like the following:
install a old version of the app;
create some data in the old version of the app;
install the new version on top it;
see if everything is migrated properly.
We have been using this migration testing method for all our previous version of the app. Our QAs will perform the above steps and then judge by themselves that whether migration is successful or not.
However, in the most recent upgrade, we have changed a lot in our data model. It doesn't sound like such a good idea to ask the QAs to remember what have been created in the old version of the app and know what have been missing or not during migration. Therefore, we would like to see whether it is possible to write unit testing for the database migration by the developers ourself.
So one of the first step is to generate test data. Notice that we can see all the previous version of the xcdatamodel from within our Xcode project, it seems that it is possible. In a nutshell, the question:
Is it possible to generate test data of previous version of xcdatamodel programmatically from within our current version of the app?
Please let me know what you think. Suggestions are also acceptable.
This is how we do it: we need to first get an URL to any model you would like to work with, and then create a managedObjectModel from it.
let oldModelUrl = NSBundle.mainBundle().URLForResource("CoreDataExample.momd/CoreDataExample",
withExtension: "mom")!
let oldManagedObjectModel = NSManagedObjectModel.init(contentsOfURL: oldModelUrl)
Referece: https://medium.com/#yzhong.cs/1d9f941b3168.
At the early stages of development, where data retention is no issue and experimental changes to the schema are expected to be numerous, is there a way to avoid migration? Namely, just to dump the database and start over each time.
Everything I try leads to the error: "The model used to open the store is incompatible with the one used to create the store".
Lightweight migration looks do-able, but I'll end up lots of unwanted versions and messy code. I'd also like to experiment with relationships (no wise cracks), but understand I'd need to commit to a heavyweight migration afterwards!
If the solution is to check for the existence of the original database using NSFileManager and delete/remove it if found, could someone please show the swift code with an example name of the original database, and how it can be effectively removed.
I've been trying several suggested solutions, such as dragging a copy of the .xcdatamodeld file onto the desktop, deleting the file in xcode and bringing it back in, but I keep getting the error that the model and store are not the same.
Answered in one line in first comment, but appreciated in reverse proportion.