zoukankan      html  css  js  c++  java
  • Hibernate 注解映射

    工作中遇到hibernate映射的一些问题,这里总结一下

    (特别是测试时,许多数据并不能有效关联。所以@NotFound 很重要)

    一,假设有2张表user,company

    我们知道,一个用户属于一个公司。那么我们这么创建Model

    //用户
    public class User
    {
    private int id;
    private String name;
    private int companyid
    
    //sub table
    private Company company;
    
    @Where(clause="IsValid=1")
    @OneToOne(fetch= FetchType.EAGER,optional = true)
    @NotFound(action= NotFoundAction.IGNORE)
    @JoinColumn(name = "companyid", referencedColumnName = "companyid",insertable = false, updatable = false)
    public Company getCompany() {
    return company;
    }
    public void setCompany(Company company) {
    this.company = company;
    }
    }
    
    
    //公司
    public class Company
    {
    private int companyid;
    private int isValid; //是否有效
    }


    二 , 解释一下

    @Where(clause="IsValid=1") 设定只查询IsValid=1的信息
    @OneToOne(fetch= FetchType.EAGER,optional = true) FetchType.EAGER 及时加载,optional = true 是否必须有值
    @NotFound(action= NotFoundAction.IGNORE) 忽略没有关联的外键
    @JoinColumn(name = "inboundOrderUUID", referencedColumnName = "inboundOrderUUID",insertable = false, updatable = false)
    name:本类的关联id referencedColumnName:关联项的id

    PS:Dao使用@Query注解,也会查询到关联对象。

  • 相关阅读:
    CodeForces
    CodeForces
    CodeForces
    CodeForces
    CodeForces
    CodeForces
    CodeForces
    CodeForces
    Code froces 831 A. Unimodal Array
    无聊随便敲敲
  • 原文地址:https://www.cnblogs.com/hanjun0612/p/10059157.html
Copyright © 2011-2022 走看看