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Spring Framework Annotation - Part 4

JPA
@Repostories
@Transactional
@PersistenceContext - for @Inject Entity Manager
@Entity on class mapped to a table
@Id
@GeneratedValue (strategy = GenerationType.AUTO)
@ManyToOne many current object to one related object.
@OneToMany one current object to many other related objects.
@JoinColumn: the column used to join two objects together.

example,

@Entity
public class Item {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;

@ManyToOne
private Order order;
}


/**
 * An order.
 */
@Entity
@Table(name="T_ORDER")
public class Order {

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private Long id;

private String customer;

@OneToMany(cascade=CascadeType.ALL)
@JoinColumn(name="ORDER_ID")
private Collection<Item> items = new LinkedHashSet<Item>();
...
}

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