Data Access Object (DAO)

Working with Interfaces

DAO is an interface that contains methods for querying the local database for data. Make sure to note the annotations used because they’re required for the methods to function.

These methods are called and implemented from the repository with the @Insert, @Query and @Delete annotations. This simplifies how we write the methods under these annotations to autogenerate the required code in the background. This way, they facilitate and decrease coding time so we can focus on the most important parts of our application.

Creating ArticleDao

We are going to use the @insert Annotation to insert articles in the articles table in the database, the onConflict parameter is set to OnConflictStrategy.REPLACE, which means that if there is a conflict, the existing row in the table will be replaced with the new data while the getAllArticles() method is used to retrieve all articles from the local database by annotating it with the @Query annotation and specify a SELECT query to retrieve all articles from all rows and columns in the articles table.

The method returns a Flow of a list of Article objects which means its an observable and we can observe it for changes and update the UI.