Core data iOS核心数据的轻量级数据迁移示例？

苹果提供了轻量级的迁移，这里是xcode4之前的好地方

在xcode4中似乎有点不同

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感谢您提供xcode4中简单示例的任何线索，以说明核心数据的数据迁移。

只需注意添加了选项NSDictionary和NSPersistentStoreCoordinator初始值设定项，现在将选项参数设置为从nil到options

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (__persistentStoreCoordinator != nil)
    {
        return __persistentStoreCoordinator;
    }

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"TradiesDB.sqlite"];

    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
                             [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];

    NSError *error = nil;
    __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error])
    {
        /*
            ...
         */
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }    

    return __persistentStoreCoordinator;
}