Realm Database Android

Posted By : Chandan Wadhwa | 07-Jun-2016

android

realm database android

Hi Folks.

Today I am going to describe about realm a new database for mobile apps.

Realm is OO database for mobile applications which is the replacement of Sqlite database. Realm store data in a universal, table-based format by a C++ core which allow data access from multiple languages as well as a range of ad hoc queries.

Realm is faster for user and easy to configure for developers. And when you need power?user features, like simple migrations, built-in encryption, and more, are all provided with realm.

Integrating realm in android

1) Adding Dependency

compile 'io.realm:realm-android:0.82.1'

2) Creating realm instance

To create a new Realm, you can call the static Realm.getInstance method from activity

Realm myRealm = Realm.getInstance(context);

3) Creating bean class which extends realmObject

public class Country extends RealmObject {
    private String name;
    private int population;

    public Country() { }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getPopulation() {
        return population;
    }

    public void setPopulation(int population) {
        this.population = population;
    }
}

4) Begin Transaction

For facilitating safe multi threading use the beginTransaction() method and to end the transaction use commitTransaction() method.

5) Insert Values

        myRealm.beginTransaction();
        // Create an object
        Country country1 = myRealm.createObject(Country.class);
        // Set its fields
        country1.setName("Norway");
        country1.setPopulation(5165800);
        myRealm.commitTransaction();

6) Select Values from table

        RealmResults<Country> results1 =
                myRealm.where(Country.class).findAll();

        for(Country c:results1) {
            Log.d("results1", c.getName());
            Log.d("results1", c.getPopulation()+"");
        }

7) Display result based on query

    public void showSelectedRecord(View v)
    {
        RealmResults results2 =
                myRealm.where(Country.class)
                        .greaterThan("population", 7000000)
                        .findAll();
        for(Country c:results2) {
            Log.d("results1", c.getName());
            Log.d("results1", c.getPopulation()+"");
        }
    }

8) Updating Record

    public void updateRecord(View v)
    {
        myRealm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                Country country3 = realm.where(Country.class).equalTo("name", "India").findFirst();
                country3.setName("Australia");
            }
        });

    }

THANKS