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我的数据模型有以下关系：

[Account] -|------o< [Transaction]

其实现为：

// in Account.h
@property (nonatomic, retain) NSSet *transactions;

// in Transaction.h
@property (nonatomic, retain) Account *account;

现在，我已经成功创建了一个 Account 并将其插入到 Core Data 中。我的问题是，如何在账户中添加起始余额？这显然只是帐户上的交易，但以下内容是否足以在数据模型中建立双向连接（即连接newAccount.transactions和连接）？newTransaction.account

// we need to insert a new account
Account *newAccount = [NSEntityDescription insertNewObjectForEntityForName:[Account entityName] inManagedObjectContext:self.managedObjectContext];

// . . . configure newAccount

NSNumber *startingBalance = @([self.startingBalanceTextField.text floatValue]);

NSError *error;

// save the new account
[self.managedObjectContext save:&error];

if( !error )
{
    Transaction *newTransaction = [NSEntityDescription insertNewObjectForEntityForName:[Transaction entityName] inManagedObjectContext:self.managedObjectContext];

    // . . . configure newTransaction

    // is this sufficient & proper? Will this add newTransaction to newAccount.transactions as well?
    newTransaction.account = newAccount;

    // save the starting balance
    [self.managedObjectContext save:&error];
}
4

1 回答 1

2

是的，如果transactions和account被定义为逆关系，那么

newTransaction.account = newAccount;

自动添加newTransaction到newAccount.transactions.

您可以轻松地在调试器中使用po newAccount.

于 2012-09-05T10:55:18.280 回答