Saving Data on Android

Question.kt
 under the 
data 
▸
 model
 package. Right now, your entity looks 
like this:
@Entity(tableName = "question", indices = 
[Index("question_id")
]) 
data
 
class
 
Question
( 
  
@PrimaryKey(autoGenerate = true)
 
  
@ColumnInfo(name = "question_id")
 
  
var
 questionId: 
Int
, 
  
val
 text: String 
)
You want to represent the difficulty in terms of numbers such as 1, 2 or 3, where 1 is 
the lowest difficulty and 3 is the highest. To represent this concept, modify your 
question class to add a 
difficulty
 property like so:
@Entity(tableName = "question", indices = 
[Index("question_id")
]) 
data
 
class
 
Question
( 
 
  
@PrimaryKey(autoGenerate = true)
 
  
@ColumnInfo(name = "question_id")
 
  
var
 questionId: 
Int
, 
  
val
 text: String, 
  
val
 difficulty: 
Int
 = 
0
 
//Only this lane changes
 
)
This property will represent the difficulty of the question and will have a default 
value of 0.
Saving Data on Android
Chapter 10: Migrations with Room
raywenderlich.com
175

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Now, build and run the app and press the 
Start
 button to see if it works.
And the app crashed!
Open the logcat console and take a look at the error displayed: