Retrieving data via services

Let's start retrieving and saving SQLite data with our service methods. It will only be necessary to update the create, update, and delete pieces of CRUD. All the media items are stored in List<MediaItem> in DataService, so the public methods used to retrieve items can remain as they were in the previous chapter. Let's get started:

1. Start by updating the create, update, and delete methods for the media items. Each of these will get an open connection to the database from GetOpenConnectionAsync and call its corresponding private method asynchronously:

   public async Task<int> AddItemAsync(MediaItem item)
   {
       using (var db = await GetOpenConnectionAsync())
       {
           return await InsertMediaItemAsync(db, item);
       }
   }
   public async Task UpdateItemAsync(MediaItem item)
   {
       using (var db = await GetOpenConnectionAsync...