云自無心水自閑

1. 數據庫的表結構
CREATE TABLE  `software` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(45) NOT NULL,
  PRIMARY KEY (`id`)
);


CREATE TABLE  `version` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `publish_time` datetime NOT NULL,
  `software_id` int(10) unsigned NOT NULL,
  PRIMARY KEY (`id`)
);

2. java的class

---------------------------------------
Software.java

import java.util.LinkedHashSet;
import java.util.Set;

import javax.persistence.Entity;

@Entity
public class Software {

    private Long id;
    private String name;
    private Set<Version> versions = new LinkedHashSet<Version>();

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
   
    @OneToMany(cascade = { CascadeType.ALL }, mappedBy="software")
    @JoinColumn(name = "software_id")
    @Fetch(FetchMode.SUBSELECT)
    @OrderBy("id")
    public Set<Version> getVersions() {
        return version;
    }

    public void setVersions(Set<Version> Versions) {
        this.versions = versions;
    }
}

-----------------------------------------------------
Version.java

import java.util.Date;
import javax.persistence.Entity;

@Entity
public class Version{
    private Long id;
    private Date publishTime;
    private Software software;
   
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }
    public Date getPublishTime() {
        return publishTime;
    }
    public void setPublishTime(Date publishTime) {
        this.publishTime = publishTime;
    }
   
    @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
    @JoinColumn(name = "software_id")
    public Software getSoftware() {
        return software;
    }

    public void setSoftware(Software software) {
        this.software = software;
    }
}

3. 測試代碼

Software software = new Software();
software.setName("Windows");

Version version = new Version;
version.setPublishTime(new Date());
version.setSoftware(software);

software.getVersions().add(version);

software.save();

hibernate會自動生成兩條insert語句，一條是software的insert語句，一條是version的insert語句。
同樣，如果刪除software的話，也會生成兩條delete語句