如何防止数据库被替换?

how do I prevent the database from being replaced?

在复制数据库之前检查目标.如果那里已经有文件，请不要进行复制.您可以使用-[NSFileManager fileExistsAtPath:]检查现有文件.

Check the destination before you copy the database. If there's already a file there, don't do the copy. You can use -[NSFileManager fileExistsAtPath:] to check for an existing file.