Android local databases
- 1. Android Local Databases By Muzamil Nawaz
- 2. Data Storage on Android • Androidprovides several optionsfor you to save your app data. • The solutionyou choose dependson your specific needs, such as how much space your datarequires, what kind of data you need to store. • Different data storage optionsavailableon Android: Internal file storage:Store app-privatefiles on the device file system. External file storage: Store files on the shared external file system. Thisis usuallyfor shared user files, such as photos. Shared preferences: Store privateprimitive data in key- value pairs. Databases : Store structured datain a private database. • Except for some types of files on external storage, all these optionsare intended for app-privatedata, the data is not naturallyaccessible to other apps.
- 3. Why SqLite?
- 4. SQLite Database for Data Storage and Retrieval SQLite is very lightweight, open source, relational database that comes with Android OS. In Android, integrating SQLite is a tedious task as it needs writing lot of boilerplate code to store simple data. Consider SQLite when your app needs to store simple and structured data objects. Alternatively, Room Persistence Library could be used for better APIs and easier integration.
- 5. SQLite Challenges Boilerplate code to convert SQL queriestoJavaData objects Database operationsonthe main thread Unmaintainable code - As your schemachangesyouneedto update the affectedSQL queriesmanually. SQL queriescheckedat runtime (Nocompile time verificationof SQLqueries) Untestable code
- 6. Room Persistence Library (RPL) Solution for the above challenges
- 7. Room Persistence Library (RPL) • Room is an abstraction on top of SQLite database. It's part of the Architecture Components by Google. • Room enables you to easily work SQLite databases in Android. • The Room persistence library acts as a layer that abstracts raw SQLite and lets you make use of robust database access while keep you close to SQLite so it doesn't get in the way when you want to access low level features of SQLite.
- 8. Components of Room Library
- 9. Components of Room Library There are 3 major components in Room: • Database : Contains the database holder and serves as the main access point for the underlying connection to your app's persisted, relational data. • Entity: Represents a table within the database. • DAO: Contains the methods used for accessing the database.
- 10. Working of RPL
- 11. Steps for making an app that uses SQLite Database to store data • Add Dependencies • Add Room Entities • Add DAO Class • Build Database
- 13. Add Dependecies • Open the application level build.gradle file and add the dependencies for Room: Implementation "android.arch.persistence.room:runt ime:1.1.0" AnnotationProcessor "android.arch.persistence.room :compiler:1.1.0" testImplementation "android.arch.persistence.room: testing:1.1.0"
- 15. Important annotations • @Entity – by using this annotation, Room will know that this class will be a table in the database and the table name will define the name of the table • @PrimaryKey – is used to set up the primary key of the table. • @ColumnInfo – defines the name of the column from the table if we don’t want to use the name of that field • You also need to add getters and setters.
- 17. Details about DAO • @Dao – by using this annotation Room knows that it should provide the implementation for our interface by generating code for the defined methods. • In this interface we could define the CRUD operations for our entity and also any other operations that are necessary in order to obtain the data. • Also Room offers us query validation at compilation time, so if we will write incorrectly the name of a table or a field we will know if after the code will be compiled.
- 18. Database Class
- 22. Got Any Questions? Please go ahead...