然后在您的应用程序委托代码文件中，在appDidFinishLaunching方法中，您需要首先检查是否已经创建了sqlite文件的可写副本 – 例如：已在用户文档文件夹中创建了sqlite文件的副本iPhone的文件系统。如果是，你不做任何事情(否则你会用默认的Xcode sqlite复制它)

如果没有，那么你复制sqlite文件在那里 – 使其可写。

看下面的代码示例来做：这是从苹果的sqlite书代码示例，其中此方法从应用程序委派appDidFinishLaunching方法调用。

// Creates a writable copy of the bundled default database in the application Documents directory.
- (void)createEditableCopyOfDatabaseIfNeeded {
    // First,test for existence.
    BOOL success;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"bookdb.sql"];
    success = [fileManager fileExistsAtPath:writableDBPath];
    if (success)
        return;
    // The writable database does not exist,so copy the default to the appropriate location.
    NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"bookdb.sql"];
    success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
    if (!success) {
        NSAssert1(0,@"Failed to create writable database file with message '%@'.",[error localizedDescription]);
    }
}

============

这里是上面的代码在Swift 2.0

// Creates a writable copy of the bundled default database in the application Documents directory.
private func createEditableCopyOfDatabaseIfNeeded() -> Void
{
    // First,test for existence.
    let fileManager: NSFileManager = NSFileManager.defaultManager();
    let paths:NSArray = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask,true)
    let documentsDirectory:NSString = paths.objectAtIndex(0) as! NSString;
    let writableDBPath:String = documentsDirectory.stringByAppendingPathComponent("bookdb.sql");

    if (fileManager.fileExistsAtPath(writableDBPath) == true)
    {
        return
    }
    else // The writable database does not exist,so copy the default to the appropriate location.
    {
        let defaultDBPath = NSBundle.mainBundle().pathForResource("bookdb",ofType: "sql")!

        do
        {
            try fileManager.copyItemAtPath(defaultDBPath,toPath: writableDBPath)
        }
        catch let unknownError
        {
            print("Failed to create writable database file with unknown error: \(unknownError)")
        }
    }
}