CODEWITHSUNDEEP
androidandroid-roomdatabase-migration
code4rox
code4rox

Reputation: 1083

Room Database migration for all version

Currently my database version is 5, I have added column to database table and changed the database version to 6, and also added migration from version 5 to 6 like this

 private static final Migration MIGRATION_5_6 = new Migration(5, 6) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
            try {
                database.execSQL("ALTER TABLE generate_data "
                        + " ADD COLUMN generateImgPath TEXT");
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    };

Question: Do I need to make migration objects for every version?

Like

MIGRATION_1_6 
MIGRATION_2_6
MIGRATION_3_6
MIGRATION_4_6
MIGRATION_5_6

Upvotes: 2

Views: 1701

Answers (1)

Praveen
Praveen

Reputation: 3486

Do I need to make migration objects for every version?

No, you don't have to create migration objects for all previous versions to the latest one. You just have to create a migration object from the second last version to the latest one.

But, for migrating users who're using an older database version, you have to add migration for every consecutive version like

MIGRATION_1_2
MIGRATION_2_3
MIGRATION_3_4
MIGRATION_4_5
MIGRATION_5_6

So that, if any user is on the oldest version of the database, then Room will run all consecutive migrations and update it to the latest version.

If you are just adding a new column to the table, going from version 5 to version 6 of the database. You can use autoMigration so you don't have to manually define the migration strategy.

For using autoMigration, like from version 5 to version 6, change version to 6, and add autoMigration to the database annotation.

@Database(
   version = 5,
   entities = [ table.class ],
   autoMigrations = [
         AutoMigration (from = 5, to = 6)
     ]
  )
abstract class YourDatabase: RoomDatabase { }

Say, you add a new column in the future version 7 too, then you can just add another AutoMigration object to the autoMigrations

 autoMigrations = [
             AutoMigration (from = 5, to = 6),
             AutoMigration (from = 6, to = 7)
         ]

Upvotes: 4

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