Hibernate：CascadeType.PERSIST不起作用，但CascadeType.ALL保存对象 [英] Hibernate : CascadeType.PERSIST does not work but CascadeType.ALL to save object

问题描述

$ 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）
私人字符串名称;

@OneToOne（可选= false，cascade = CascadeType.PERSIST）
@JoinColumn（name =Exch_ID）
私人交易所交易所;

// ---构造函数和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）
私人字符串名称;

@OneToOne（mappedBy =exchange）
private section section;

// ----------- Getter和Setter ...和构造函数

}

以下程序不起作用 - >

  final SessionFactory sessionFactory = configuration.buildSessionFactory（）; 
 final Session session = sessionFactory.openSession（）; 
 session.beginTransaction（）; 
 
最终兑换兑换=新兑换（MyExchange）; 
 final Section section = new Section（MySection，exchange）; 
 exchange.setSection（section）; 
 session.save（section）; 
 
 session.getTransaction（）。commit（）; 
 session.close（）; 
  

如果我将Section.java中的级联选项更改为CascadeType.ALL，那么它可以工作。

  @OneToOne（可选= false，cascade = CascadeType.PERSIST）---> CascadeType.ALL 
 @JoinColumn（name =Exch_ID）
私人交换交换; 
  

我认为PERSIST应该保存我的对象d =，但是会抛出异常：

org.hibernate.TransientPropertyValueException：非空属性引用临时值 - 在当前操作之前必须保存临时实例：Section.exchange - > Exchange

解决方案

对于要级联的 save（）操作，您需要启用 CascadeType.SAVE_UPDATE ，使用专有的Hibernate Cascade 注释，因为save（）不是标准的JPA操作。或者您需要使用 persist（）方法，而不是 save（）方法。

@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

}

The following program does not work ->

    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();

If i change cascade options in Section.java to CascadeType.ALL then it works.

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

I think PERSIST should save my object d=, but it throws exception :

org.hibernate.TransientPropertyValueException: Not-null property references a transient value - transient instance must be saved before current operation: Section.exchange -> Exchange

解决方案

For the save() operation to be cascaded, you need to enable CascadeType.SAVE_UPDATE, using the proprietary Hibernate Cascade annotation, since save() is not a standard JPA operation. Or you need to use the persist() method, and not the save() method.

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