Xtykutl

I'm trying to create two tables in the app. One table contains just two fields: String and Date, while another table consists of three fields: all 3 Strings.

Is it enough to create a single database class which extends RoomDatabase or is it needed to create two database classes for each table?

Kindly provide me any sample code if available. Thanks in advance.

you can create as many table as you want to in single database.

// table 1

@Entity(tableName = Constants.TABLE_NAME_DRINK_TYPE)

public class DrinkType {

@PrimaryKey(autoGenerate = true)

private int id;

@ColumnInfo(name ="icon")

private int icon;

@ColumnInfo(name ="quantity")

private int quantity;





public DrinkType(int icon, int quantity) {

    this.icon = icon;

    this.quantity = quantity;



}





public DrinkType() {

}







public int getId() {

    return id;

}



public void setId(int id) {

    this.id = id;

}



public int getIcon() {

    return icon;

}



public void setIcon(int icon) {

    this.icon = icon;

}



public int getQuantity() {

    return quantity;

}



public void setQuantity(int quantity) {

    this.quantity = quantity;

}

}

table 2

// table 2

@Entity(tableName = Constants.TABLE_NAME_WEIGHT)

public class Weight {

@PrimaryKey(autoGenerate = true)

private int uid;



@ColumnInfo(name = "weight_value")

private int weightValue;

@ColumnInfo(name = "weight_unit")

private String weightUnit;

@ColumnInfo(name = "dateTime")

private long dateTime;

@ColumnInfo(name ="date")

private String date;



public Weight(int uid, int weightValue, String weightUnit, long dateTime, String date) {

    this.uid = uid;

    this.weightValue = weightValue;

    this.weightUnit = weightUnit;

    this.dateTime = dateTime;

    this.date = date;

}



public Weight() {

}





public int getUid() {

    return uid;

}



public void setUid(int uid) {

    this.uid = uid;

}



public int getWeightValue() {

    return weightValue;

}



public void setWeightValue(int weightValue) {

    this.weightValue = weightValue;

}



public String getWeightUnit() {

    return weightUnit;

}



public void setWeightUnit(String weightUnit) {

    this.weightUnit = weightUnit;

}



public long getDateTime() {

    return dateTime;

}



public void setDateTime(long dateTime) {

    this.dateTime = dateTime;

}



public String getDate() {

    return date;

}



public void setDate(String date) {

    this.date = date;

}

}

main database class. in this class you have to define every table class inside entities annotation tag

// database class

@Database(entities = {Weight.class, DrinkType.class}, version = 1, exportSchema = false)

public abstract class MyDataBase extends RoomDatabase {

public abstract WeightDao weightDao();

// DAO classes



public abstract DrinkTypeDao drinkTypeDao();



private static MyDataBase dataBase;



public static MyDataBase getInstance(Context context){

    if (null== dataBase){

        dataBase= buildDatabaseInstance(context);

    }

    return dataBase;

}



private static MyDataBase buildDatabaseInstance(Context context) {

    return Room.databaseBuilder(context,

            MyDataBase.class,

            Constants.DB_NAME)

            .allowMainThreadQueries().build();

}

}

You create a single Database and include all your tables an entity and also include each table DAO e.g

@Database(entities = {Table1.class,Table2.class,Table3.class}, version = 1,exportSchema = false)

@TypeConverters(DateConverter.class)

public abstract class AppDatabase extends RoomDatabase {

    private static AppDatabase sInstance;

    private static final Object LOCK = new Object();

    private static final String DATABASE_NAME = "instant Error";





    public static AppDatabase getInstance(Context context) {



        if(sInstance==null){

            synchronized (LOCK){

                sInstance = Room.databaseBuilder(context.getApplicationContext(),AppDatabase.class,DATABASE_NAME)

                        .build();

            }



        }

        return sInstance;

    }



    public abstract Table1 table1Dao();

    public abstract Table2 table2Dao();

    public abstract Table3 table3Dao();

}