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hibernate一对一映射关系

2017-09-12 11:33 295 查看
一、需求: 用户与身份证信息

一条用户记录对应一条身份证信息! 一对一的关系!

设计数据库:

JavaBean:

映射:



二、基于外键的映射

[java] view
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<span style="font-family:KaiTi_GB2312;">// 身份证

public class IdCard {

// 身份证号(主键)

private String cardNum;// 对象唯一表示(Object Identified, OID)

private String place; // 身份证地址

// 身份证与用户,一对一的关系

private User user;</span>

[java] view
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<span style="font-family:KaiTi_GB2312;">// 用户

public class User {

private int userId;

private String userName;

// 用户与身份证信息, 一对一关系

private IdCard idCard;</span>

IdCard.hbm.xml有外键方:

[html] view
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<span style="font-family:KaiTi_GB2312;"><?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<hibernate-mapping package="cn.lfsenior.c_one2one">

<class name="IdCard" table="t_IdCard">

<id name="cardNum">

<generator class="assigned"></generator>

</id>

<property name="place" length="20"></property>

<!--

一对一映射,有外键方

unique="true" 给外键字段添加唯一约束

-->

<many-to-one name="user" unique="true" column="user_id" class="User" cascade="save-update"></many-to-one>

</class>

</hibernate-mapping></span>

User.hbm.xml无外键方

[html] view
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<span style="font-family:KaiTi_GB2312;"><?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<hibernate-mapping package="cn.lfsenior.c_one2one">

<class name="User" table="t_user">

<id name="userId">

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

</id>

<property name="userName" length="20"></property>

<!--

一对一映射: 没有外键方

-->

<one-to-one name="idCard" class="IdCard"></one-to-one>

</class>

</hibernate-mapping>

</span>

三、基于主键的映射

[java] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;">// 身份证

public class IdCard {

private int user_id;

// 身份证号

private String cardNum;

private String place; // 身份证地址

// 身份证与用户,一对一的关系

private User user;</span>

IdCard.hbm.xml

[html] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;"><?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<hibernate-mapping package="cn.lfsenior.c_one2one2">

<class name="IdCard" table="t_IdCard">

<id name="user_id">

<!--

id 节点指定的是主键映射, 即user_id是主键

主键生成方式: foreign 即把别的表的主键作为当前表的主键;

property (关键字不能修改)指定引用的对象 对象的全名 cn..User、 对象映射 cn.User.hbm.xml、 table(id)

-->

<generator class="foreign">

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

</generator>

</id>

<property name="cardNum" length="20"></property>

<property name="place" length="20"></property>

<!--

一对一映射,有外键方

(基于主键的映射)

constrained="true" 指定在主键上添加外键约束

-->

<one-to-one name="user" class="User" constrained="true" cascade="save-update"></one-to-one>

</class>

</hibernate-mapping>

</span>

User.hbm.xml

[html] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;"><?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<hibernate-mapping package="cn.lfsenior.c_one2one2">

<class name="User" table="t_user">

<id name="userId">

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

</id>

<property name="userName" length="20"></property>

<!--

一对一映射: 没有外键方

-->

<one-to-one name="idCard" class="IdCard"></one-to-one>

</class>

</hibernate-mapping>

</span>

一、需求: 用户与身份证信息

一条用户记录对应一条身份证信息! 一对一的关系!

设计数据库:

JavaBean:

映射:



二、基于外键的映射

[java] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;">// 身份证

public class IdCard {

// 身份证号(主键)

private String cardNum;// 对象唯一表示(Object Identified, OID)

private String place; // 身份证地址

// 身份证与用户,一对一的关系

private User user;</span>

[java] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;">// 用户

public class User {

private int userId;

private String userName;

// 用户与身份证信息, 一对一关系

private IdCard idCard;</span>

IdCard.hbm.xml有外键方:

[html] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;"><?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<hibernate-mapping package="cn.lfsenior.c_one2one">

<class name="IdCard" table="t_IdCard">

<id name="cardNum">

<generator class="assigned"></generator>

</id>

<property name="place" length="20"></property>

<!--

一对一映射,有外键方

unique="true" 给外键字段添加唯一约束

-->

<many-to-one name="user" unique="true" column="user_id" class="User" cascade="save-update"></many-to-one>

</class>

</hibernate-mapping></span>

User.hbm.xml无外键方

[html] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;"><?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<hibernate-mapping package="cn.lfsenior.c_one2one">

<class name="User" table="t_user">

<id name="userId">

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

</id>

<property name="userName" length="20"></property>

<!--

一对一映射: 没有外键方

-->

<one-to-one name="idCard" class="IdCard"></one-to-one>

</class>

</hibernate-mapping>

</span>

三、基于主键的映射

[java] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;">// 身份证

public class IdCard {

private int user_id;

// 身份证号

private String cardNum;

private String place; // 身份证地址

// 身份证与用户,一对一的关系

private User user;</span>

IdCard.hbm.xml

[html] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;"><?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<hibernate-mapping package="cn.lfsenior.c_one2one2">

<class name="IdCard" table="t_IdCard">

<id name="user_id">

<!--

id 节点指定的是主键映射, 即user_id是主键

主键生成方式: foreign 即把别的表的主键作为当前表的主键;

property (关键字不能修改)指定引用的对象 对象的全名 cn..User、 对象映射 cn.User.hbm.xml、 table(id)

-->

<generator class="foreign">

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

</generator>

</id>

<property name="cardNum" length="20"></property>

<property name="place" length="20"></property>

<!--

一对一映射,有外键方

(基于主键的映射)

constrained="true" 指定在主键上添加外键约束

-->

<one-to-one name="user" class="User" constrained="true" cascade="save-update"></one-to-one>

</class>

</hibernate-mapping>

</span>

User.hbm.xml

[html] view
plain copy

print?

<span style="font-family:KaiTi_GB2312;"><?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC

"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

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

<hibernate-mapping package="cn.lfsenior.c_one2one2">

<class name="User" table="t_user">

<id name="userId">

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

</id>

<property name="userName" length="20"></property>

<!--

一对一映射: 没有外键方

-->

<one-to-one name="idCard" class="IdCard"></one-to-one>

</class>

</hibernate-mapping>

</span>
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