hibernate外键映射到唯一键

Question

我正在尝试我们非主键作为外键在我的应用程序。场景如下：我有EMPLOYEE和EMPLOYEE_PROPERTIES表。Employee和Employee属性之间存在一对多的关系。下面是我的架构：

create table employee(
 fname varchar2(100) not null,
 lname varchar2(100) not null,
 emp_id number not null
);
ALTER TABLE employee ADD constraint employee_pk PRIMARY KEY (fname, lname);
alter table employee add constraint employee_uniue unique (emp_id);

create table employee_property(
 emp_prop_id not null,
 emp_id number not null,
 property_name varchar2(100) not null,
 property_value varchar2(100) not null
);
ALTER TABLE employee_property ADD constraint employee_property_pk PRIMARY KEY (emp_prop_id);
ALTER TABLE employee_property ADD CONSTRAINT emp_prop_fk FOREIGN KEY (emp_id) REFERENCES employee(emp_id);

下面是我的hibernate映射XML:-------------------------------

<hibernate-mapping>
    <class name="com.persistence.vo.Employee" table="EMPLOYEE">
        <composite-id>
            <key-property name="fName" column="FNAME"/>
            <key-property name="lName" column="LNAME"/>
        </composite-id>
        <property name="empId" type="long" access="field" unique="true">
            <column name="EMP_ID" />
        </property>
        <set name="employeeProperties" table="employee_properties" lazy="false"
            fetch="select" cascade="save-update, delete-orphan">
            <key>
                <column name="emp_id" not-null="true"/>
            </key>
            <one-to-many entity-name="com.persistence.vo.EmployeeProperty"/>
        </set>
    </class>
</hibernate-mapping>

-------------员工属性-------------------

<hibernate-mapping>
    <class name="com.persistence.vo.EmployeeProperty" table="EMPLOYEE_PROPERTY">
        <id name="empPropId" type="long">
            <column name="EMP_PROP_ID" />
            <generator class="assigned" />
        </id>
    <many-to-one name="employee" class="com.persistence.vo.Employee" fetch="select">
        <column name="empId" not-null="true"/>
    </many-to-one>
        <property name="propertyName" type="java.lang.String">
            <column name="PROPERTY_NAME" />
        </property>
        <property name="propertyValue" type="java.lang.String">
            <column name="PROPERTY_VALUE" />
        </property>
    </class>
</hibernate-mapping>

public class Employee {

    private long empId;
    private String fName;
    private String lName;

    private Set<EmployeeProperty> employeeProperties;
}

public class EmployeeProperty {

    private long empPropId;
    private Employee employee;
    private String propertyName;
    private String propertyValue;
}

是否可以引用非主键作为外键？

Answer 1

我被你的地图弄糊涂了。Employee到EmployeeProperty是一对多的，但EmployeeProperty中的emp_id在映射中标记为此实体的ID字段（即PK，唯一列）？

您有多种选项：

[1]向EmployeeProperty添加另一个字段以充当ID,例如emp_property_id