Cannot save data model that contains List with Room ORM Kotlin

Question

I have a problem with Room ORM working on Kotlin. My task is having ability to save and get data models RouteTemplateModel, that contains list of addresses of type AddressModel and object of class RouteModel that contains title of the specific route. Here is my code:

AddressModel.kt

@Entity(foreignKeys = arrayOf(
                        ForeignKey(entity = RouteModel::class,
                        parentColumns = arrayOf("routeId"),
                        childColumns = arrayOf("parentId"))))
data class AddressModel(
   @PrimaryKey(autoGenerate = true)
            var addressId: Long,
            var parentId: Long,
            var street: String,
            var house: String,
            var entrance: String,
            var title: String){
            constructor(): this(0, 0, "", "", "", "")         
}        

RouteModel.kt

@Entity
data class RouteModel(
    @PrimaryKey(autoGenerate = true)
    var routeId: Long,
    var title: String) {
    constructor() : this(0, "")
}

Here is my simple models, I found in documentation of Room that for creating relations between models I need to use @ForeignKey and @Relation

So with code samples in doc and tutorials I create RouteTemplateModel that contains object of RouteModel and list of AddressModels. Here is the class

RouteTemplateModel

class RouteTemplateModel{

    private var id: Long = 0

    @Embedded
    private var routeModel: RouteModel = RouteModel()

    @Relation(parentColumn = "routeId", entityColumn = "parentId")
    private var addressList: List<AddressModel> = listOf()

    constructor()

    constructor(id: Long, routeModel: RouteModel, title: String,
                addressList: List<AddressModel>){
        this.id = id
        this.routeModel = routeModel
        this.addressList = addressList
    }

    fun getId(): Long{
        return id
    }

    fun getRouteModel(): RouteModel{
        return routeModel
    }

    fun getAddressList(): List<AddressModel>{
        return addressList
    }

    fun setId(id: Long){
        this.id = id
    }

    fun setRouteModel(routeModel: RouteModel){
        this.routeModel = routeModel
    }

    fun setAddressList(addressList: List<AddressModel>){
        this.addressList = addressList
    }

}

So what`s a problem? I am getting such errors:

Error:The columns returned by the query does not have the fields [id] in com.innotech.webcab3kotlin.model.RouteTemplateModel even though they are annotated as non-null or primitive. Columns returned by the query: [routeId,title]

And

Error:Type of the parameter must be a class annotated with @Entity or a collection/array of it.

It is a real problem, because if my trying to fix first error and annotate in RouteTemplateModel id variable to return this column too, I need annotate class as Entity (like in second error), but when I do it I am getting an error

Error:Entities cannot have relations.

Here is AppDatabase.kt

@Database(entities = arrayOf(RouteModel::class, AddressModel::class), version = 1)
abstract class AppDatabase : RoomDatabase() {

    abstract fun getRouteDao(): RouteDao
}

and RouteDao.kt

@Dao
interface RouteDao {


    @Query("SELECT routeId, title FROM RouteModel")
    fun getAll(): List<RouteTemplateModel>

    @Insert
    fun insertAll(vararg models: RouteTemplateModel)

    @Delete
    fun delete(model: RouteTemplateModel)


}

Thats really confusing. Please, help me)

Answer 1

Your "parentId" column is capable of holding long value only, make its type to "Text" then create a TypeConverter from "List" to String and vice a versa for reference please have a look at link .