`CHEESE_DATA.map { Cheese(id = 0, name = it) }` `CHEESE_DATA` is an ArrayList. If we apply `map` wi...

# getting-started

[Sudhir Singh Khanger]

CHEESE_DATA.map { Cheese(id = 0, name = it) }

CHEESE_DATA is an ArrayList. If we apply map with the above function then should it not create a list of Cheese objects with id 0 and name it. The result seems to be Cheese object with an incremented value for id and it name. What am I missing?

https://github.com/googlesamples/android-architecture-components/blob/6248bed977e7a82d6f3199e8a940a39b7d6f051c/PagingSample/app/src/main/java/paging/android/example/com/pagingsample/CheeseDb.kt#L54

[Andreas Sinz]

Maybe auto generated id by room?

[luke]

The ID is an auto-incrementing primary key: https://github.com/googlesamples/android-architecture-components/blob/6248bed977e7a82d6f3199e8a940a39b7d6f051c/PagingSample/app/src/main/java/paging/android/example/com/pagingsample/Cheese.kt#L26

[luke]

For more information on how Room treats that annotation, see: https://developer.android.com/reference/android/arch/persistence/room/PrimaryKey#autogenerate

[Sudhir Singh Khanger]

Thanks. That's right.

But otherwise my assertion would be correct.

[Andreas Sinz]

@Sudhir Singh Khanger your assertion is correct, map doesn't change id, room does it

[Sudhir Singh Khanger]

Thanks.