Saving data to a database is ideal for repeating or structured data,
such as contact information. This page assumes that you are
familiar with SQL databases in general and helps you get started with
SQLite databases on Android. The APIs you'll need to use a database
on Android are available in the android.database.sqlite package.
Caution: Although these APIs are powerful, they are fairly low-level and require a great deal of time and effort to use:
- There is no compile-time verification of raw SQL queries. As your data graph changes, you need to update the affected SQL queries manually. This process can be time consuming and error prone.
- You need to use lots of boilerplate code to convert between SQL queries and data objects.
For these reasons, we highly recommended using the Room Persistence Library as an abstraction layer for accessing information in your app's SQLite databases.
Define a schema and contract
One of the main principles of SQL databases is the schema: a formal declaration of how the database is organized. The schema is reflected in the SQL statements that you use to create your database. You may find it helpful to create a companion class, known as a contract class, which explicitly specifies the layout of your schema in a systematic and self-documenting way.
A contract class is a container for constants that define names for URIs