![]() ![]() The first step to creating an app that reads from a SQLite database is to decide on a database schema. Overall, this section will give you a greater understanding and appreciation for the new and improved Room Persistence Libraries. However, if you have never seen an app that utilizes the SQLite APIs, this section will show you an example of how to use them in your apps. If you have written an app in the past that utilizes the SQLite APIs in Java, this chapter will show you how to use them with Kotlin, instead. Another is that you need to write a lot of boilerplate code to connect and transform SQL queries and data objects. One disadvantage to using the SQLite APIs is that there is no compile-time verification of the raw SQL queries, and if the database structure changes, the affected queries have to be updated manually. Currently, it’s recommended to use the Room Persistence Library instead, which will provide an abstraction layer for accessing the data in your app’s SQLite databases. It’s capable of creating in-memory databases, which are very fast to work with.Īndroid provides the APIs necessary to create and interact with SQLite databases in the package.Īlthough these APIs are powerful and familiar to many developers, they are low-level and do require some time and effort to use.It allows a single database connection to access multiple database files simultaneously.This means you can store a value in any column, regardless of the data type. Some distinctive features of SQLite include: SQLite is a library that provides a DBMS, based on SQL. The default database management system (DBMS) that Android uses is called SQLite. ![]() However, sometimes an app needs to store larger amounts of data in a more structured manner, which usually requires a database. Using Files and Shared Preferences are two excellent ways for an app to store small bits of data. Introduction to Cloud Firestoreġ7.2 Cloud Firestore vs. Realtime Database Offline Capabilitiesġ5.2 Other offline scenarios and network connectivity features Reading to & Writing from Realtime Database Introduction to Firebase Realtime Database Using Firebase Section 3: 11 chapters Show chapters Hide chapters Using Room with Android Architecture Components Using Room Section 2: 6 chapters Show chapters Hide chaptersĦ.2 Room and Android Architecture ComponentsĨ.2 Relations and entity-relationship diagrams Here is how the UserDatabase.Saving Data Using Android SDK & Jetpack DataStore Section 1: 5 chapters Show chapters Hide chaptersġ.3 Viewing the files in Device File Explorerġ.5 Understanding Parcelization and SerializationĢ.2 Getting a reference to the SharedPreferences fileĢ.6 Reading and writing the prefs from MainActivityĤ.1 Understanding content provider basicsĤ.3 Implementing the content provider methods We also need to call the build() method over it to actually build an instance of the database. To get an instance of the database, we will use Room.databaseBuilder() which requires 3 arguments namely context, current class, and name of the database. The class must have an abstract function of the same type as your DAO.Ĭreate a new companion object in this class which will hold a variable of the type of the class set to null, 2 functions to get and destroy the instance of the class. exportSchema that enables the version history of your schema in your codebase.version which is the database version, and.entities which takes a list of the entity,.This class should be annotated with annotation with arguments: Query annotation requires a value argument which must be an SQL command to query on the database.Ĭreate a new abstract class named UserDatabase which extends to RoomDatabase while instantiating it. I recommended this as it saves time and effort. If you wish, you can have an autogenerating id for the database using the = true) annotation. UserDatabase.kt which will host an abstract class of the database with a companion object to make the instance singleton.ĭatabase instance created must be a singleton as recommended by official documentation on Ĭreate a new data class named User which will take some argument to store in the database.UserDAO.kt which will contain an interface hosting our methods to perform over the database like insert, update, etc, and.User.kt which will contain the data class of the User object we will insert in the database,.To use the room library, I will create a new package that will store all the files related to it, named database. You can check the complete list of arguments supported and their use cases on Enter fullscreen mode Exit fullscreen mode
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