休眠：CascadeType.PERSIST不工作，但CascadeType.ALL保存對象

Question

@Entity 
@Table(name = "Section_INST") 
public class Section { 

@javax.persistence.Id 
@GeneratedValue(strategy = GenerationType.SEQUENCE,generator = "Section_ID_GENERATOR") 
@SequenceGenerator(name = "Section_ID_GENERATOR",sequenceName = "Section_ID_SEQUENCER" , initialValue = 1 , allocationSize = 1) 
@Column(name = "Section_ID") 
private int Id; 

@Column(name = "Section_Name") 
private String name; 

@OneToOne(optional = false,cascade = CascadeType.PERSIST) 
@JoinColumn(name = "Exch_ID") 
private Exchange exchange; 

//---Constructor and Getter Setters----- 
} 


@Entity 
@Table(name = "EXCHANGE_INST") 
public class Exchange { 

@Id 
@GeneratedValue(strategy = GenerationType.SEQUENCE,generator = "Exchange_ID_GENERATOR") 
@SequenceGenerator(name = "Exchange_ID_GENERATOR",sequenceName = "Exchange_ID_SEQUENCER" , initialValue = 1 , allocationSize = 1) 
@Column(name = "Exchange_ID") 
private int Id; 

@Column(name = "Exchange_name") 
private String name; 

@OneToOne(mappedBy ="exchange") 
private Section section; 

//-----------Getter and Setter...And Constructor 

}

下面的程序無法正常工作 - >

final SessionFactory sessionFactory = configuration.buildSessionFactory(); 
    final Session session = sessionFactory.openSession(); 
    session.beginTransaction(); 

    final Exchange exchange = new Exchange("MyExchange"); 
    final Section section = new Section("MySection" , exchange); 
    exchange.setSection(section); 
    session.save(section); 

    session.getTransaction().commit(); 
    session.close(); 

如果我在Section.java改變級聯選項。到CascadeType.ALL然後它工作。

@OneToOne(optional = false,cascade = CascadeType.PERSIST) --- > CascadeType.ALL 
@JoinColumn(name = "Exch_ID") 
private Exchange exchange; 

我覺得PERSIST要救我的對象d =，但它拋出異常：

org.hibernate.TransientPropertyValueException：非空屬性引用瞬態值 - 瞬態實例必須當前操作之前被保存： Section.exchange - >交易所

Answer 1

對於save()操作進行級聯，則需要啓用CascadeType.SAVE_UPDATE，使用專用的休眠Cascade註釋，因爲保存（）是不是一個標準的JPA操作。或者您需要使用persist()方法，而不是save()方法。