Saving Data on Android

QuizDatabase.kt
 under the 
data 
▸
 db
 package and increase the database 
version by changing the 
version
 parameter value to 2 in the 
@Database
 notation:
@Database(entities = [(Question::class)
, (Answer::
class
)], 
version = 2) //version change
 
abstract
 
class
 
QuizDatabase
 : 
RoomDatabase
() { 
  
abstract
 
fun
 
questionsDao
()
: QuestionDao 
}
Build and run the app again and press 
START
....
And the app crashes again!
Open the logcat console to see the problem. You should see the message below:
A migration from 1 to 2 was required but not found. Please provide the necessary 
Migration path via RoomDatabase.Builder.addMigration(Migration ...) or allow for 
destructive migrations via one of the 
RoomDatabase.Builder.fallbackToDestructiveMigration
 methods.*
It looks like you're making some progress, since the error is different now. The error 
indicates that Room doesn't know how to change the database schema from 1 to 2, 
so it's giving you two options:
• Create a migration that goes from database schema 1 to 2.
• Call 
fallbackToDestructiveMigration()
 when building your database.
Saving Data on Android
Chapter 10: Migrations with Room
raywenderlich.com
177

---

The second option is the easiest one to implement since you only need to add a 
single line of code. The only problem with this approach is that you will lose all your 
data when changing the schema from version 1 to 2. This is fine for your app since 
you have a handy button to populate your database in the main menu, but it might 
not be a good idea for other projects where you want to preserve user data.
With the above in mind, you're going to follow the first approach and create a new 
migration. Create a new package under the