Hibernate学习7（映射组成关系）

一张表对应 一组对象

如员工信息 和工资休假 业务是分开 但可以存放在一张表里

• 子对象（员工工资休假对象）不具有OID属性

package chen;

public class Pay {
    private int pay;//工资
    private int annualLeave;//假期
    
    public int getPay() {
        return pay;
    }
    public void setPay(int pay) {
        this.pay = pay;
    }
    public int getAnnualLeave() {
        return annualLeave;
    }
    public void setAnnualLeave(int annualLeave) {
        this.annualLeave = annualLeave;
    }
}

• 主对象（员工基本信息）具有OID属性

package chen;

public class Staff {
    private Integer id;
    private String name;
    private Pay pay;//工资

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public Pay getPay() {
        return pay;
    }

    public void setPay(Pay pay) {
        this.pay = pay;
    }
}

配置

• component标签配置 name属性主对象对应属性名 class属性是子对象的全类名
• component标签 使用property子标签指定属性与列名对应关系

<hibernate-mapping package="chen">
    <class name="Staff" table="STAFF">
        <id name="id" type="java.lang.Integer">
            <column name="ID" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="NAME" />
        </property>
        <!-- 映射组成关系 -->
        <component name="pay" class="Pay">
            <!-- 指定组成关系属性 -->
            <property name="annualLeave" column="annualLeave"></property>
            <property name="pay" column="pay"></property>
        </component>
    </class>
</hibernate-mapping>

代码使用：

    /**
     * 映射组成关系
     * 一个对象由多个对象组成的映射
     * 
     */
    public static void testRelation() {
        StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure().build();// 配置文件configure()
        SessionFactory sessionFactory = new MetadataSources(registry).buildMetadata().buildSessionFactory();
        Session session = sessionFactory.openSession();
        Transaction transaction = session.beginTransaction();

        Staff staff = new Staff();
        staff.setName("张三");

        Pay pay = new Pay();
        pay.setAnnualLeave(5);
        pay.setPay(100000);
        staff.setPay(pay);
        session.save(staff);

        transaction.commit();
        session.close();
        sessionFactory.close();
    }

数据库

一张表对应 一组对象

如员工信息 和工资休假 业务是分开 但可以存放在一张表里

• 子对象（员工工资休假对象）不具有OID属性

package chen;

public class Pay {
    private int pay;//工资
    private int annualLeave;//假期
    
    public int getPay() {
        return pay;
    }
    public void setPay(int pay) {
        this.pay = pay;
    }
    public int getAnnualLeave() {
        return annualLeave;
    }
    public void setAnnualLeave(int annualLeave) {
        this.annualLeave = annualLeave;
    }
}

• 主对象（员工基本信息）具有OID属性

package chen;

public class Staff {
    private Integer id;
    private String name;
    private Pay pay;//工资

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public Pay getPay() {
        return pay;
    }

    public void setPay(Pay pay) {
        this.pay = pay;
    }
}

配置

• component标签配置 name属性主对象对应属性名 class属性是子对象的全类名
• component标签 使用property子标签指定属性与列名对应关系

<hibernate-mapping package="chen">
    <class name="Staff" table="STAFF">
        <id name="id" type="java.lang.Integer">
            <column name="ID" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="NAME" />
        </property>
        <!-- 映射组成关系 -->
        <component name="pay" class="Pay">
            <!-- 指定组成关系属性 -->
            <property name="annualLeave" column="annualLeave"></property>
            <property name="pay" column="pay"></property>
        </component>
    </class>
</hibernate-mapping>

代码使用：

    /**
     * 映射组成关系
     * 一个对象由多个对象组成的映射
     * 
     */
    public static void testRelation() {
        StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure().build();// 配置文件configure()
        SessionFactory sessionFactory = new MetadataSources(registry).buildMetadata().buildSessionFactory();
        Session session = sessionFactory.openSession();
        Transaction transaction = session.beginTransaction();

        Staff staff = new Staff();
        staff.setName("张三");

        Pay pay = new Pay();
        pay.setAnnualLeave(5);
        pay.setPay(100000);
        staff.setPay(pay);
        session.save(staff);

        transaction.commit();
        session.close();
        sessionFactory.close();
    }

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• 只是业务上分开 表还是一张

• 只是业务上分开 表还是一张