Hibernate: ids for this class must be manually assigned before calling save()

Question

I am having some problems with Hibernate and the oneToMany mapping.

Here is my function:

        Location location = new Location();
                


        

Answer 1

Assign primary key in hibernate

Make sure that the attribute is primary key and Auto Incrementable in the database. Then map it into the data class with the annotation with @GeneratedValue annotation using IDENTITY.

@Entity
@Table(name = "client")
data class Client(
        @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "id") private val id: Int? = null
)

GL

Source

Answer 2

your id attribute is not set. this MAY be due to the fact that the DB field is not set to auto increment? what DB are you using? MySQL? is your field set to AUTO INCREMENT?