与预填充sqlite的核心数据关系

Question

首先，对不起。 我不擅长英语。 你好 我是iOS的初学者。

目前，我正在这样开发：

1. 删除自动生成的核心数据sqlite文件
2. 使用firefox sqlite管理器将我创建的sqlite文件复制到已删除的sqlite文件路径
   （使用Z_PK，Z_ENT，Z_OPT的sqlite）

两个问题：

1. 如何使用firefox sqlite管理器创建实体关系。
2. 在详细的核心数据选项（例如关系删除规则，sqlite管理器上的属性属性）或其他任何内容的情况下，如何预先创建。

Answer 1

好吧，基本上，您需要保留一个由项目使用架构创建的空数据库，然后对其进行处理以保存所需的数据。 更多信息在这里

链接中未描述另一种方法，即使用Core Data本身（和一个SQLite库读取其他数据库）将数据库中的数据复制到Core Data数据库中。

Answer 2

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

NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"CoreDataBooks.CDBStore"];

/*
 Set up the store.
 For the sake of illustration, provide a pre-populated default store.
 */
NSFileManager *fileManager = [NSFileManager defaultManager];
// If the expected store doesn’t exist, copy the default store.
if (![fileManager fileExistsAtPath:[storeURL path]]) {
    NSURL *defaultStoreURL = [[NSBundle mainBundle] URLForResource:@"CoreDataBooks" withExtension:@"CDBStore"];
    if (defaultStoreURL) {
        [fileManager copyItemAtURL:defaultStoreURL toURL:storeURL error:NULL];
    }
}

NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];

NSError *error;
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error]) {
    /*
     Replace this implementation with code to handle the error appropriately.

     abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 

     Typical reasons for an error here include:
     * The persistent store is not accessible;
     * The schema for the persistent store is incompatible with current managed object model.
     Check the error message to determine what the actual problem was.


     If the persistent store is not accessible, there is typically something wrong with the file path. Often, a file URL is pointing into the application's resources directory instead of a writeable directory.

     If you encounter schema incompatibility errors during development, you can reduce their frequency by:
     * Simply deleting the existing store:
     [[NSFileManager defaultManager] removeItemAtURL:storeURL error:nil]

     * Performing automatic lightweight migration by passing the following dictionary as the options parameter:
     @{NSMigratePersistentStoresAutomaticallyOption:@YES, NSInferMappingModelAutomaticallyOption:@YES}

     Lightweight migration will only work for a limited set of schema changes; consult "Core Data Model Versioning and Data Migration Programming Guide" for details.

     */
    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}

return _persistentStoreCoordinator;

从Apple文档获取的代码Core Data Books 链接您需要具有一个预先填充的数据库数据，该数据库已通过Core Data进行了填充。 该功能在应用程序首次启动时将预填充的数据库复制到主数据库存储位置。

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