Implementing DAO with CRUD Operations

Introduction

The data stored in SQLite tables can generally be accessed using SQL queries. Writing boilerplate code for CRUD (Create, Read, Write, and Delete) operations feels repetitive if our application contains multiple tables. The Room persistence library lets us define a Data Access Object (DAO), a wrapper with convenient methods to interact with the underlying SQLite database.

Defining a DAO

Room provides the Dao annotation, which can be added to an interface or an abstract class. We can define methods to perform CRUD operations on the Room entities in the DAO class.

To refresh our memories, let’s take a look at the User entity. The User entity represents the User table in the SQLite database.