Spring Data Jpa Entity RelationShip Mappings @OneToMany Unidirection (No middle table)

Java Entities

PurchaseOrder Entity

@Entity
@Data
@NoArgsConstructor
@NamedQuery(name="PurchaseOrder.findById_named", query = " FROM PurchaseOrder p JOIN FETCH p.items i WHERE p.id = :id")
@Table(name = "purchase_order", schema = "public")
public class PurchaseOrder {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO,generator = "public.purchase_order_seq")
    private Long id;
    private String name;
    @OneToMany( cascade = CascadeType.ALL, targetEntity = Item.class)  //default targetEntity can be omitted
    @JoinColumn(name = "purchase_order_id_fk",      // default is "item.items_id" And Avoids the creation of extra Table
                referencedColumnName = "id")        // default could be omitted
    private List<Item> items = new ArrayList<>();

Item Entity

@Entity
@Data
@NoArgsConstructor
@Table(name = "item", schema = "public")
public class Item {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO,generator = "public.item_seq")
    private Long id;
    private String name;

Hibernate creates automatically the tables the next way

Hibernate: 

    

    create table public.item (

       id int8 not null,

        name varchar(255),

        purchase_order_id_fk int8,

        primary key (id)

    )

Hibernate: 

    

    create table public.purchase_order (

       id int8 not null,

        name varchar(255),

        primary key (id)

    )

Hibernate: 

    

    alter table if exists public.item 

       add constraint FK1ohvucgh093bf3fnpbhhitv47 

       foreign key (purchase_order_id_fk) 

       references public.purchase_order

Test the behaviour

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