Hibernate saves child entity with null parent id - spring

Question

Hibernate doesn't want to save IDs for child entities. I have the following tables:
#Entity
#Table(name = "ct_orders")
data class Order(
#Id
#Column(name = "id")
#GeneratedValue(strategy = javax.persistence.GenerationType.IDENTITY)
val id: Int = 0,
#OneToMany(fetch = FetchType.LAZY, cascade = arrayOf(CascadeType.ALL), mappedBy = "order")
val route: List<Route>? = null,
...
)
#Entity
#Table(name = "ct_routes")
#JsonIgnoreProperties("id", "order")
data class Route(
#Id
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
val id: Int = 0,
#Column
val location: Point = GeoHelpers.point(),
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "order_id")
val order: Order? = null,
#Column
val title: String = ""
)
ct_routes saving with null in order_id. Is there some problem with relationships? Or, may be there is something wrong in my code?
Here is the part of code, which saves an Order entity:
val order = orderRepository.save(Order(
...
route = GeoHelpers.placesListToEntities(data.places),
...
))
fun placesListToEntities(points: List<PlaceDto>) = points.map {
Route(
location = Helpers.geometry(it.location.latitude, it.location.longitude),
title = it.title
)
}

Answer 1

You're modeling bidirectional #OneToMany and as shown in the example in the documentation you're responsible for setting the parent value on the child entity:
val order = orderRepository.save(Order(...).apply{
...
route = GeoHelpers.placesListToEntities(this, data.places),
...
})
fun placesListToEntities(order:Order, points: List<PlaceDto>) = points.map {
Route(
order = order,
location = Helpers.geometry(it.location.latitude, it.location.longitude),
title = it.title
)
}
PS. Since Route is an entity you could change your model a bit to enforce the constraints on the langauge level i.e:
class Route internal constructor() {
lateinit var order: Order
constructor(order: Order) : this() {
this.order = order
}
}
See this question for more details.