. Hibernate one-to-one mapping and component mapping

1. Follow the foreign key mapping ( Hibernate provides two ways to map one-to-one relationships: by foreign key mapping and by primary key mapping

Implementation needs:

Create an entity class Users1 and Resume1

Public class Users1 {

Private Integer userid;

Private String username;

Private String Userpass;

Private Resume1 resume1;

}

***********

Public class Resume1 {

Private Integer Resid;

Private String Resname;

Private String Rescardno;

Private Users1 users1;

}

-----------------------

configuration file Users1.hbm.xml and Resume1.hbm.xml:

Users1.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>

<! DOCTYPE hibernate-mapping Public

"-//hibernate/hibernate Mapping DTD 3.0//en"

"Http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd" >

"CN.HAPPY.ONETOONE_FK">

<class name="Users1" table="USERS1">

<id name="userid " column="userid " >

<generator class="native"></generator>

</id>

<property name="username" column="username" type="string"></property>

<property name="Userpass" column="Userpass" type="string"></property>

<one-to-one name="resume1" class="Resume1" property-ref="users1" ></one-to-one >

</class>

*********************

Resume1.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>

<! DOCTYPE hibernate-mapping Public

"-//hibernate/hibernate Mapping DTD 3.0//en"

"Http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd" >

"CN.HAPPY.ONETOONE_FK">

<class name="Resume1" table="RESUME1">

<id name="Resid" column="Resid" >

<generator class="native"></generator>

</id>

<property name="Resname" column="Resname" type="string"></property>

<property name="Rescardno" column="Rescardno" type="string"></property >

<many-to-one name="users1" class="Users1" cascade="All" column="Resuserid " Unique="true"></many-to-one>

</class>

------------------------------------

2. Primary KEY Mapping

Implementation needs:

Create entity Classes Users2 and Resume2

Public class Users2 {

Private Integer userid;

Private String username;

Private String Userpass;

Private Resume2 resume2;

}

******************* :

Public class Resume2 {

Private Integer Resid;

Private String Resname;

Private String Rescardno;

Private Users2 users2;

}

----------------------------

configuration file Users1.hbm.xml and Resume1.hbm.xml

Users1.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>

<! DOCTYPE hibernate-mapping Public

"-//hibernate/hibernate Mapping DTD 3.0//en"

"Http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd" >

"CN.HAPPY.ONETOONE_PK">

<class name="Users2" table="USERS2">

<id name="userid " column="userid " >

<generator class="foreign">

<param name="property">resume2</param>

</generator>

</id>

<property name="username" column="username" type="string"></property>

<property name="Userpass" column="Userpass" type="string"></property>

<one-to-one name="resume2" class="Resume2" constrained="true"></one-to-one >

</class>

************************

Resume2.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>

<! DOCTYPE hibernate-mapping Public "-//hibernate/hibernate mapping DTD 3.0//en"

"Http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd" >

"CN.HAPPY.ONETOONE_PK">

<class name="Resume2" table="RESUME2">

<id column="RESID" name="RESID">

<generator class="native"/>

</id>

<property column="Resname" name="Resname" type="string"/>

<property column="Rescardno" name="Rescardno" type="string"/>

<one-to-one name="users2" cascade="All" class="Users2"/>

</class>

==========================================

One. component Mapping (an important principle of establishing a relational data model is to minimize the number of database tables and the foreign key references between tables without causing data redundancy)

Implementation requirements:

Creating Emphomeaddress and empinfo

Public class emphomeaddress {

Private String Ehomestreet;

Private String ehomecity;

Private String ehomeprovince;

Private String Ehomezipcode;

Private Empinfo Empinfo;

}

--------------

Public class Empinfo {

Private Integer Eid;

Private String ename;

Private Emphomeaddress ehome;

}

*************************

Creating a configuration file EmpInfo.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>

<! DOCTYPE hibernate-mapping Public

"-//hibernate/hibernate Mapping DTD 3.0//en"

"Http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd" >

"Cn.happy.component">

<class name="Empinfo" table="Empinfo">

<id name="Eid " column="Eid" >

<generator class="native"></generator>

</id>

<property name="ename" column="ename" type="string"></property>

<component name="ehome" class="emphomeaddress">

<parent name="Empinfo"/>

<property name="Ehomestreet" column="Ehomestreet" type="string"></property >

<property name="ehomecity" column="ehomecity" type="string"></property>

<property name="ehomeprovince" column="ehomeprovince" type="string"></ Property>

<property name="Ehomezipcode" column="Ehomezipcode" type="string"></ Property>

</component>

</class>

. Hibernate one-to-one mapping and component mapping