Question

我在我的应用中将预装的核心数据包含为3个捆绑文件（.sqlite，.sqlite-shm，.sqlite-wal），并在用户下载应用时将其用作主要核心数据。

这就是我在AppDelegate.swift中的内容

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = {
    // The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
    // Create the coordinator and store
    var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
    let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("coreDB.sqlite")




    /******************** If core data is empty, import from the bundle *******************/
    if !NSFileManager.defaultManager().fileExistsAtPath(url.path!) {
        let sourceSqliteURLs = [NSBundle.mainBundle().URLForResource("coreDB", withExtension: "sqlite")!, NSBundle.mainBundle().URLForResource("coreDB", withExtension: "sqlite-wal")!, NSBundle.mainBundle().URLForResource("coreDB", withExtension: "sqlite-shm")!]

        let destSqliteURLs = [self.applicationDocumentsDirectory.URLByAppendingPathComponent("coreDB.sqlite"),
            self.applicationDocumentsDirectory.URLByAppendingPathComponent("coreDB.sqlite-wal"),
            self.applicationDocumentsDirectory.URLByAppendingPathComponent("coreDB.sqlite-shm")]

        var error:NSError? = nil
        for var index = 0; index < sourceSqliteURLs.count; index++ {
            do {
                try NSFileManager.defaultManager().copyItemAtURL(sourceSqliteURLs[index], toURL: destSqliteURLs[index])
            } catch var error1 as NSError {
                error = error1
            } catch {
                fatalError()
            }
        }
    }


var error: NSError? = nil
    var failureReason = "There was an error creating or loading the application's saved data."
    do {
        try coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true])
    } catch var error1 as NSError {
        error = error1
        coordinator = nil
        // Report any error we got.
        var dict = [String: AnyObject]()
        dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data"
        dict[NSLocalizedFailureReasonErrorKey] = failureReason
        dict[NSUnderlyingErrorKey] = error
        error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
        // Replace this 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.
        NSLog("Unresolved error \(error), \(error!.userInfo)")
        //abort()
    } catch {
        fatalError()
    }

    return coordinator
}()

现在我不得不从核心数据中更改一些数据，所以这就是我所做的：

1）使用xcode从核心数据更改一些数据，以便在iOS模拟器中运行应用程序时更改数据

2）找到属于iOS模拟器的.sqlite，.sqlite-shm，sqlite-wal文件

3）将这3个文件拖到xcode中，并将它们包含在应用程序包中

4）当用户更新应用程序时，如何使新更新的应用程序用这3个文件替换其核心数据？是什么叫Lightmigration这个问题的解决方案？

Answer 1

我在我的一个应用程序中执行相同操作，所有与sqlite相关的文件都与应用程序捆绑在一起，在第一次启动时我将它们复制到一个目录中，该路径由使用应用程序版本号组成。

- (NSString *)applicationDatabaseDirectory
{
    NSString * documentsDir = [self applicationDocumentsDirectory];
    NSString * databasePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:@"Database/%@",[self appVersionString]]];
    NSFileManager * fileManager = [[NSFileManager alloc] init];
    BOOL isDir = YES;
    if (![fileManager fileExistsAtPath:databasePath isDirectory:&isDir]) {
        [fileManager createDirectoryAtPath:databasePath withIntermediateDirectories:YES attributes:nil error:nil];
    }
    return databasePath;
}
- (NSString *) appVersionString {
    return  [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];
}

请记住，每次向模型添加一些新属性时，都必须使用迁移更新捆绑包中的数据库，然后再次复制文件，删除旧文件。

如何使用应用商店中的新版本替换iOS应用中预先填充的核心数据？

1 个答案: