删除文件夹

    //获取路径  

    NSString *fileName = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES)lastObject] stringByAppendingPathComponent:@"Code.sqlite"];

  [[NSFileManagerdefaultManager] removeItemAtPath:fileNameerror:nil];

清楚数据库的话 这块将数据库再关闭一下

   [queue close];