ORMLite is an Object Relational Mapping package that provides simple and lightweight functionality for persisting Java objects to SQL databases while avoiding the complexity and overhead of more standard ORM packages.

Speaking for Android, OrmLite is implemented over the out-of-the-box supported database, SQLite. It makes direct calls to the API to access SQLite.

Gradle setup

To get started you should include the package to the build gradle.

// <https://mvnrepository.com/artifact/com.j256.ormlite/ormlite-android>
compile group: 'com.j256.ormlite', name: 'ormlite-android', version: '5.0'
POJO configuration

Then you should configure a POJO to be persisted to the database. Here care must be taken to the annotations:

• Add the @DatabaseTable annotation to the top of each class. You can also use @Entity.
• Add the @DatabaseField annotation right before each field to be persisted. You can also use @Column and others.
• Add a no-argument constructor to each class with at least package visibility.

@DatabaseTable(tableName = "form_model")
public class FormModel implements Serializable {

   @DatabaseField(generatedId = true)
   private Long id;
   @DatabaseField(dataType = DataType.SERIALIZABLE)
   ArrayList<ReviewItem> reviewItems;

   @DatabaseField(index = true)
   private String username;

   @DatabaseField
   private String createdAt;

   public FormModel() {
   }

   public FormModel(ArrayList<ReviewItem> reviewItems, String username, String createdAt) {
       this.reviewItems = reviewItems;
       this.username = username;
       this.createdAt = createdAt;
   }
}

At the example above there is one table (form_model) with 4 fields.

id field is auto generated index.

username is an index to the database.

More information about the annotation can be found at the official documentation.

Database Helper

To continue with, you will need to create a database helper class which should extend the OrmLiteSqliteOpenHelper class.

This class creates and upgrades the database when your application is installed and can also provide the DAO classes used by your other classes.

DAO stands for Data Access Object and it provides all the scrum functionality and specializes in the handling a single persisted class.

The helper class must implement the following two methods:

• onCreate(SQLiteDatabase sqliteDatabase, ConnectionSource connectionSource);