休眠一對多級聯效率

過去幾周我一直在學習Hibernate，我已經獲得了大部分我學會的工作，但對一對多映射的效率有疑問。它的工作原理，但我很確定它可以調整很多。保存時，我注意到有三個查詢被執行，一個是「Parent」對象的插入，一個是「Child」對象的插入，然後是更新父對象外鍵的子查詢。我的假設是有一種更有效的方式來映射這種關係，以便只有兩個插入。我在映射中丟失了一些相對明顯的東西嗎？休眠一對多級聯效率

這裏是我的代碼：

家長：

@Entity 
@Table(name="Punch") 
public class Punch implements Serializable 
{ 
    private Long id; 
    private DateTime punchDate; 
    private Integer userId; 
    private List<PunchTimes> punches= new ArrayList<PunchTimes>(); 
    private static final long serialVersionUID=2010010611; 
    ...Various getters & setters... 
    @OneToMany 
    @JoinColumn(name="punchId_fk") 
    @OrderBy("pid") 
    @Cascade(org.hibernate.annotations.CascadeType.ALL) 
    public List<PunchTimes> getPunches() 
    { 
     return punches; 
    } 
}

兒童：

@Entity 
@Table(name = "PunchTimes") 
public class PunchTimes implements Serializable{ 
    private Long id; 
    private Long pid; 
    private DateTime inTime; 
    private DateTime outTime; 
    private Double adjustedTime; 
    private static final long serialVersionUID = 20100106; 
    private Punch punch; 
    ...Various getters & setters... 
    @ManyToOne 
    @JoinColumn(name = "punchId_fk", insertable = false, updatable = false) 
    public Punch getPunch(){ 
     return punch; 
    } 
}

SQL輸出：

insert into Punch (punchDate, employeeId) 
values (?, ?) 

insert into PunchTimes (adjusted, inTime, outTime, punchId_fk) 
values (?, ?, ?, ?) 

update PunchTimes 
set punchId_fk=? 
where inoutId=?

來源

2010-01-12 nelsonslament

import java.io.Serializable; 
import javax.persistence.*; 
import org.hibernate.annotations.Type; 
import org.joda.time.DateTime; 

@Entity 
@Table(name = "PunchTimes") 
public class PunchTimes implements Serializable 
{ 
    private static final long serialVersionUID = 20100106; 
    private Long id; 
    private Long pid; 
    private DateTime inTime; 
    private DateTime outTime=null; 
    private Double adjustedTime=null; 
    private Boolean adjustedByOperator=false; 
    private Boolean overtimeAuthorized; 
    private Punch punch; 

    public PunchTimes() 
    { 
    } 

    @Column(name = "adjusted") 
    public Double getAdjustedTime() 
    { 
     return adjustedTime; 
    } 

    public void setAdjustedTime(Double adjustedTime) 
    { 
     this.adjustedTime = adjustedTime; 
    } 

    @Id 
    @GeneratedValue 
    @Column(name = "inoutId") 
    public Long getId() 
    { 
     return id; 
    } 

    public void setId(Long id) 
    { 
     this.id = id; 
    } 

    @Column(name = "inTime") 
    @Type(type = "org.joda.time.contrib.hibernate.PersistentDateTime") 
    public DateTime getInTime() 
    { 
     return inTime; 
    } 

    public void setInTime(DateTime inTime) 
    { 
     this.inTime = inTime; 
    } 

    @Column(name = "outTime") 
    @Type(type = "org.joda.time.contrib.hibernate.PersistentDateTime") 
    public DateTime getOutTime() 
    { 
     return outTime; 
    } 

    public void setOutTime(DateTime outTime) 
    { 
     this.outTime = outTime; 
    } 

    @Column(name = "punchId_fk" ,insertable = false, updatable = false) 
    public Long getPid() 
    { 
     return pid; 
    } 

    public void setPid(Long pid) 
    { 
     this.pid = pid; 
    } 

    @ManyToOne 
    @JoinColumn(name = "punchId_fk") 
    public Punch getPunch() 
    { 
     return punch; 
    } 

    public void setPunch(Punch punch) 
    { 
     this.punch = punch; 
    }

爲了擺脫更新，我必須使外鍵（pid）可插入= false，updatable = false

來源

2010-03-05 20:48:29 nelsonslament

休眠一對多級聯效率

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