How do POST with JSON with OneToMany?-CodePudding

I am using SpringBoot, so lets say first, I want to make a Country, and after doing that POST with JSON how can I do other POST to create a City and adding it to the Country created?

Or I cant do it with JSON?

And idk if is a good idea having the FK pointing the name instead of the ID, in my head it works the same bc is an unique key, right?

Thanks!

Country code:

@Entity
@Table(uniqueConstraints = {
        @UniqueConstraint(name = "country_name",columnNames = "name")
})
@Getter @Setter @RequiredArgsConstructor @NoArgsConstructor @ToString
public class Country implements Serializable {
    @Id
    @Column(updatable = false, nullable = false, unique = true)
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @NonNull
    private String name;

    @OneToMany(mappedBy = "country", cascade = CascadeType.ALL, orphanRemoval = true)
    private Set<City> cities = new HashSet<>();

}

City code:

@Entity
@Table(uniqueConstraints = {
        @UniqueConstraint(name = "city_name",columnNames = "name")

})
@Getter @Setter @RequiredArgsConstructor @NoArgsConstructor @ToString
public class City implements Serializable {
    @Id
    @Column(updatable = false, nullable = false, unique = true)
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    @NonNull
    private String name;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "country_name", referencedColumnName = "name", nullable = false,
            foreignKey=@ForeignKey(name = "FK_country_city"))
    private Country country;

    @OneToMany(mappedBy = "city", cascade = CascadeType.ALL, orphanRemoval = true)
    private Set<Neighborhood> neighborhoods = new HashSet<>();
    
}

Neiborhood code:

@Entity
@Table(uniqueConstraints = {
        @UniqueConstraint(name = "neighborhood_name",columnNames = "name")
})
@Getter @Setter @RequiredArgsConstructor @NoArgsConstructor @ToString
public class Neighborhood implements Serializable {

    @Id
    @Column(updatable = false, nullable = false, unique = true)
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    @NonNull
    private String name;
    @NonNull
    private String neighborhoodType;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "city_name", referencedColumnName = "name", nullable = false,
            foreignKey=@ForeignKey(name = "FK_city_neighborhood"))
    private City city;

}

CodePudding user response：

So first you need to do the POST request to create Country object:

{
    "name": "USA",
    "cities": []
}

Second you need to do the POST request to create the City object and put the field country with the Primary Key (PK):

{
    "name": "Huston",
    "country": 1,
    "neighborhoods": []
}

That's pretty much it actually.