Room database upgrade

• First class inheritance among RoomBase definition Migration
  • 　　

        static Migration migration = new Migration(1,2) {
            @Override
            public void migrate(@NonNull SupportSQLiteDatabase database) {
                database.execSQL("alter table student_table ADD  COLUMN begin_time INTEGER NOT NULL DEFAULT 0");
            }
        };

     

• RooDataBase (). AddMigrations (migration) .build
  • 　　

    Room.databaseBuilder(mContext.getApplicationContext(),WorkRoomDataBase.class,"work_database")
                                .addMigrations(ALL_MIGRATIONS)
            ....

     

• Note that the definition INTEGER field when the need to add NOT NULL DEFAULT 0, otherwise the report was wrong (IlegalStateException)