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无法将数据错误与coredata合并

[英]Can't merge data error with coredata

原文 2011-03-16 19:22:25 9 1 cocoa/ core-data

I have an app that uses coredata, but when I accidentally open the app 2 times from different locations I get his error message "can't merge data" when trying to close the app. 我有一个使用coredata的应用程序，但是当我不小心从不同位置两次打开该应用程序时，尝试关闭该应用程序时，都会收到他的错误消息“无法合并数据”。

How can I prevent the other app from opening? 如何防止其他应用打开？ Or is there a way to merge the info? 还是有一种合并信息的方法？ Thanks, Jose 谢谢，何塞

1 个解决方案

Core Data lacks concurrency locking so you can't have two apps accessing the same store file at the same time. Core Data缺乏并发锁定，因此您不能让两个应用程序同时访问相同的存储文件。 Core Data isn't a database system but rather an object graph management system that provides the model layer for Model-View-Controller design app. 核心数据不是数据库系统，而是对象图管理系统，它为Model-View-Controller设计应用程序提供了模型层。 If you try to use it like a database system you will come to grief. 如果您尝试将其像数据库系统一样使用，您将不胜其烦。

The usually solution to the problem you describe is to create a library directory that contains subdirectories for each instance of the app and put each instance's store in its own dedicated directory so the problem does not occur. 解决您描述的问题的通常方法是创建一个库目录，其中包含该应用程序的每个实例的子目录，并将每个实例的存储区放置在其自己的专用目录中，这样就不会发生此问题。

You can build a small server with Core Data that will provide distributed objects to other processes in a reasonably efficient manner. 您可以使用Core Data构建小型服务器，该服务器将以合理有效的方式向其他进程提供分布式对象。 If you have multiple processes that all need the same persistent store, that would be your best bet. 如果您有多个都需要同一个持久性存储的进程，那将是最好的选择。

See Marcus S. Zarra's Core Data book for an example of how to do this. 有关如何执行此操作的示例，请参见Marcus S. Zarra的核心数据书。