Strange Core Data Error During Migration - core-data

Question

I'm absolutely pulling my hair out with Core Data after yet another bizarre error that I can't seem to solve.
This will be the fourth version of the Data model, the previous migrations have worked (albeit with some headaches).
All I'm trying to do is add a property of String type to an 'Engines' entity. I create a new version of the model (version 4) based on the current version (v3). I select the newly created version 4 as the 'Current model' and add the string property to the Engines entity. I then create a new mapping model, using v3 as the source and v4 as the target. I delete the previous Engines NSManagedObject subclass, and create a new one using the new, modified Engines entity, checking to make sure that the new String property is in the header file. I clean build the app and run it, and boom! I get this error, about 18 times:
{NSDetailedErrors=(
"Error Domain=NSCocoaErrorDomain Code=1570 \"The operation couldn\U2019t be completed. (Cocoa error 1570.)\" UserInfo=0x6015820 {NSValidationErrorObject= (entity: BodySet; id: 0x60ba670 ; data: ), NSValidationErrorKey=availableCar, NSLocalizedDescription=The operation couldn\U2019t be completed. (Cocoa error 1570.)}",
BodySet is another entity in the model, but I haven't touched it during this migration, so why is it causing all these errors?
I'm not sure if this is a help or not, but here's my Core Data code:
- (NSManagedObjectContext *) managedObjectContext {
if (managedObjectContext != nil) {
return managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
managedObjectContext = [[NSManagedObjectContext alloc] init];
[managedObjectContext setPersistentStoreCoordinator: coordinator];
}
return managedObjectContext;
}
- (NSManagedObjectModel *)managedObjectModel {
if (managedObjectModel != nil) {
return managedObjectModel;
}
NSString *path = [[NSBundle mainBundle] pathForResource:#"CoreDataTest" ofType:#"momd"];
NSURL *momURL = [NSURL fileURLWithPath:path];
managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:momURL];
return managedObjectModel;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if (persistentStoreCoordinator != nil) {
return persistentStoreCoordinator;
}
stringByAppendingPathComponent:#"<Project Name>.sqlite"]];
//get the DB from the Documents directory:
NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory]
stringByAppendingPathComponent: #"<Project Name>.sqlite"]];
NSLog(#"Loading DB at path: %#", [storeUrl path]);
NSError *error = nil;
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc]
initWithManagedObjectModel:[self managedObjectModel]];
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
[NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
if(![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
configuration:nil URL:storeUrl options:options error:&error]) {
/*Error for store creation should be handled in here*/
NSLog(#"Something went wrong....%#", [error description]);
}
return persistentStoreCoordinator;
}
Any help with this is very much appreciated.

Answer 1

i have fixed it ，maybe you can change "availableCar“ item to optional