hibernate零散知识点

name中的字段就是javabean中的蓝色字段


字段名跟数据库的列名一样时就可以省略column，不一样就必须写column


column是数据库中的列名


inverse（反转引擎）




----------------------------------------------------
<?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">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="doubleorm.Teacher" schema="NEIL">
       <id name="tid">
        <generator class="assigned"></generator>
       </id>
       <property name="tname"/>
       <!--  inverse="true",关系反转，由对方来维护这种关联（由多的一方来关联一的一方） -->
       <set name="students" cascade="all" inverse="true">
        <!-- key是主键,one-to-many外键的一方 -->
        <key column="tid"/>
        <one-to-many class="doubleorm.Student"/>
       </set>
       
    </class>
</hibernate-mapping>
------------------------------------------------------
若某列有默认约束，则*.hbm.xml文件这样写：


<property name="sname" type="java.lang.String" insert="false"/>


-----------------------------------------------------------------------
<set name="teachers" table="st"  cascade="all" fetch="join">
        <!-- key是主键,one-to-many外键的一方 -->
        <key column="sid"/>
        <many-to-many column="tid"  class="doublemany2many.Teacher"/>
       </set>
 fetch="join" 默认是join，查询时SQL语句是联合查询的，若换成select则SQL语句是两条，subselect是子查询


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


MyObject.java:


package com.ruicaiedu.domain;


public class MyObject {
// private int mid;
private String mid;
private String mname;

// public int getMid() {
// return mid;
// }
// public void setMid(int mid) {
// this.mid = mid;
// }

public String getMname() {
return mname;
}
public String getMid() {
return mid;
}
public void setMid(String mid) {
this.mid = mid;
}
public void setMname(String mname) {
this.mname = mname;
}

}
-----------------------------------------------------------------------
MyObject.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">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
<!-- schema="NEIL":用户名 catalog=""数据库-->
    <class name="com.ruicaiedu.domain.MyObject" table="myobject" schema="NEIL" >
<!--         <id name="mid" type="java.lang.Integer" column="mid"> -->
<id name="mid" type="java.lang.String" column="mid" length="40">
<!--             <generator class="increment" /> 自动增长-->
<!-- 序列 -->
<!-- <generator class="sequence"> -->
<!-- <param name="sequence">my_seq</param> -->
<!-- </generator> -->
<!-- <generator class="uuid"></generator> -->
<generator class="assigned"></generator>
        </id>
        <property name="mname" type="java.lang.String" column="mname"  length="30" >
        </property>        
    </class>
</hibernate-mapping>
-----------------------------------------------------------------------


Userinfo.java:


package com.ruicaiedu.domain;


public class Userinfo implements java.io.Serializable{


/**
* 
*/
private static final long serialVersionUID = 1L;


private String userid;
private String userpwd;
public String getUserid() {
return userid;
}
public void setUserid(String userid) {
this.userid = userid;
}
public String getUserpwd() {
return userpwd;
}
public void setUserpwd(String userpwd) {
this.userpwd = userpwd;
}

}
--------------------------------------------------------------------------


Userinfo.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">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
<!-- schema="NEIL":用户名 catalog=""数据库-->
    <class name="com.ruicaiedu.domain.Userinfo" table="eg_table" schema="NEIL" dynamic-insert="true" >
        <id name="userid" type="java.lang.String" column="aaa" length="30" >
            <generator class="assigned" />
        </id>
        <property name="userpwd" type="java.lang.String" column="bbb">
        </property>
        
    </class>
</hibernate-mapping>