近兩天來在研究Hibernate中的one-to-one和one-to-many的問題，做了很多試驗，發現實現表關系時，在hibernate-mapping中generator的class設為uuid.hex，上述的兩種關系可以實現，也就是數據庫的主鍵設為varchar（MSSQL2000），但是主鍵改成int型的標識卻彈出“ERROR SessionImpl:2379 - Could not synchronize database state with session”和“net.sf.hibernate.HibernateException: SQL insert, update or delete failed (row not found)”異常，百思不得其解。下面貼出主鍵設為uuid.hex時的實現代碼：

Child.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping SYSTEM "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
<hibernate-mapping>
??? <class name="test.pojo.Child" table="child">
??????? <id name="cid" column="cid" >
??????????? <generator class="uuid.hex"/>
??????? </id>
??????? <property name="cname" column="cname" />
??????? <many-to-one name="parent" column="pid" />
??? </class>
</hibernate-mapping>

Child.java

package test.pojo;

public class Child {
??? private String cname;
??? private String pid;
??? private Parent parent;
??? private String cid;
??? public Child() {
??? }

??? public String getCid() {
??????? return cid;
??? }

??? public void setCid(String cid) {
??????? this.cid = cid;
??? }

??? public String getCname() {
??????? return cname;
??? }

??? public void setCname(String cname) {
??????? this.cname = cname;
??? }

??? public String getPid() {
??????? return pid;
??? }

??? public void setPid(String pid) {
??????? this.pid = pid;
??? }

??? public Parent getParent() {
??????? return parent;
??? }

??? public void setParent(Parent parent) {
??????? this.parent = parent;
??? }
}

Parent.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping SYSTEM "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
<hibernate-mapping>
??? <class name="test.pojo.Parent" table="parent" >
??????? <id name="pid" column="pid" type="integer">
??????????? <generator class="uuid.hex" />
??????? </id>
??????? <property name="pname" column="pname" />
??????? <set name="child" lazy="true" inverse="true" cascade="all">
??????????? <key column="cid" />
??????????? <one-to-many class="capinfo.negroup.test.pojo.Child"/>
??????? </set>
??? </class>
</hibernate-mapping>

Parent.java
package test.pojo;

import java.util.HashSet;

public class Parent {
??? private String pname;
??? private java.util.Set child = new HashSet();
??? private String pid;
??? public Parent() {
??? }

??? public String getPid() {
??????? return pid;
??? }

??? public void setPid(String pid) {
??????? this.pid = pid;
??? }

??? public String getPname() {
??????? return pname;
??? }

??? public void setPname(String pname) {
??????? this.pname = pname;
??? }

??? public java.util.Set getChild() {
??????? return child;
??? }

??? public void setChild(java.util.Set child) {
??????? this.child = child;
??? }

}

TestHibernate.java
package test.pojo;

public class TestHibernate {
??? public TestHibernate() {
??? }

??? public static void main(String[] argv) {
??????? //先建立多的初始數據
??????? Child child = new Child();
??????? child.setCname("kerry");
??????? //再建立一的初始數據
??????? Parent parent = new Parent();
??????? parent.setPname("Kelphen");
??????? //將多的數據放入到一里
??????? parent.getChild().add(child);
??????? //再將一放到多里，這樣一與多互相擁有對方
??????? child.setParent(parent);
??????? try {
??????????? BaseDAOHibernate.saveObject(parent);
??????? }
??????? catch (DAOException daoe) {
??????????? daoe.printStackTrace();
??????? }
??? }
}