Hibernate - 从内连接查询结果获取对象值时触发选择查询

Question

主表对象：

@Entity
@Table(name = "master")
public class Master implements Serializable {
@Id
@GeneratedValue
@Column(name = "id")
private int id;

@Column(name = "name")
private String name;
@OneToMany
@JoinColumns({
    @JoinColumn(updatable = false, insertable = false, name = "name", referencedColumnName = "name"),
    @JoinColumn(updatable = false, insertable = false, name = "id", referencedColumnName = "id")
})
private Set<Child> chld= new HashSet<Child>(0);

public int getId() {
    return id;
}

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

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public Set<Child> getChld() {
    return chld;
}

public void setChld(Set<Child> chld) {
    this.chld= chld;
}
}

子表对象：

@Entity
@Table(name = "temptest")
public class TableObject implements Serializable {


@Column(name = "name")
private String name;
@Id
@GeneratedValue
@Column(name = "p_id")
private int p_id;
@Column(name = "id")
private String id;

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}   


public int getP_id() {
    return p_id;
}

public void setP_id(int p_id) {
    this.p_id = p_id;
}

public String getId() {
    return id;
}

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

内部加入代码：

        Criteria cr1 = session.createCriteria(Master.class, "m");            
        cr1.createAlias("chld", "c", Criteria.INNER_JOIN);   
        List list = cr1.list();            
        Master m= (Master) list.get(0);
        System.out.println("Master name>" + m.getName());
        Set set = m.getChld();
        System.out.println("set count" + set.size());
        Iterator it = set.iterator();
        while (it.hasNext()) {
            Child chld= (Child ) it.next();
             System.out.println("chld name"+chld.getName());

        }

当我运行此代码时，会形成内部联接查询并返回结果集。

14:31:09,343 INFO [STDOUT] Hibernate: select this_.name as name189_1_, this_.id as id189_1_, c1_.p_id as p1_188_0_, c1_.id as id188_0_, c1_.name as name188_ 0_ from master this_ inner join child c1_ on this_.name=c1_.name and thi s_.id=c1_.id

在Master对象中消耗了结果。但问题是，在检索Master对象内部可用的Child对象时。

Set set = m.getChld();

再次触发选择查询以从子表中获取记录

14:31:09,343 INFO [STDOUT] Hibernate: select chld0_.name as name189_1_, chld0 _.id as id189_1_, chld0_.p_id as p1_1_, chld0_.p_id as p1_188_0_, chld0_.id a s id188_0_, chld0_.name as name188_0_ from child chld0_ where chld0_.name= ? and chld0_.id=?

请咨询，这是Hibernate的正常行为还是我在这里缺少任何东西，