Question

我不想在保存父实体上选择子集合

我有父/子关系，子集合被映射为懒惰。我取一个父，当然因为延迟加载子集合没有加载。但是当我想更新我的父亲时，第一个子集合正在加载，那么父正在更新。性能问题！怎么解决？

＆＃13;

Parent entity :
@Entity
@Table(name = "LOAN")
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class Loan implements java.io.Serializable {

private Long id;
private Set<VchN> vchNs=new HashSet<VchN>(0);
private Set<VchN2> vchNs2=new HashSet<VchN2>(0);
.
.
.
.
private Set<VchN100> vchNs100=new HashSet<VchN100>(0);

/*
	id setter getter
*/
@OneToMany(fetch = FetchType.LAZY)
@JoinColumn(name = "loan_id", insertable = false,updatable = false)
public Set<VchN> getVchNs() {
        return vchNs;
}

public void setVchNs(Set<VchN> vchNs) {
        this.vchNs = vchNs;
}

/*

setters getters

*/


}


Child enity:

@Entity
@Table(name = "VCH_N")
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class VchN implements java.io.Serializable {

private Loan loan;
@Column(name = "loan_id", nullable = false)
public Long getLoanId() {
        return loanId;
}

public void setLoanId(Long loanId) {
        this.loanId = loanId;
}

}

so on......

＆＃13;

Now when I execute
loanRepository.save(loan);

Output:
select columns from VchN where loan_id=?
select columns from VchN2 where loan_id=?
.
.
.
select columns from VchN100 where loan_id=?
update Loan set column = ?

I just want to update parent entity.

Answer 1

尝试双向关系。在VchN实体上，在Loan属性上指定@ManyToOne批注。删除Loan实体中每个VchN集合属性的@JoinColumn批注。而是将@JoinColumn注释放在VchN实体类的loan属性上。通过使用@OneToMany批注的mappedby属性，指定Loan实体是关系的反面。

以下示例：

public class Loan implements java.io.Serializable {
...
@OneToMany(fetch = FetchType.LAZY, mappedBy="loan")
public Set<VchN> getVchNs() {
        return vchNs;
}
...

public class VchN implements java.io.Serializable {
...
@ManyToOne
@JoinColumn(name = "loan_id")
public Loan getLoan() {
        return loan;
}
...

停止加载子集合，如果我更新父集合

1 个答案: