100分求助:hibernate操作Oracle的时候主键的问题.

Order.java
/*
* Created on Mar 5, 2004
*
* (c) 2004, Mark Eagle, [email protected]
* relased under terms of the GNU public license
* http://www.gnu.org/licenses/licenses.html#TOCGPL
*/
package com.meagle.bo;import java.util.HashSet;
import java.util.Set;/**
* This object represents an order.
*
* @hibernate.class table="Orders"
*
* @author meagle
*/
public class Order { private String id;

private double total;

// The person that placed the order as a simple String
// to keep the example small
private String userName;

// collection of order line items
private Set orderLineItems = new HashSet(); /**
* Default constuctor
*/
public Order() {
super();
} /**
* @hibernate.id generator-class="native" type="int" column="Order_ID" unsaved-value="0"
* @return int
*/
public String getId() {
return id;
}

/**
* @hibernate.set name="orderLineItems" table="OrderLineItem"
* inverse="true"
* cascade="save-update" lazy="true"
* @hibernate.collection-key column="Order_ID"
* @hibernate.collection-one-to-many class="com.meagle.bo.OrderLineItem"
*
*  @return Set
*/
public Set getOrderLineItems() {
return orderLineItems;
} /**
* @hibernate.property column="UserName" type="string" not-null="true" unique="false"
* @return String
*/
public String getUserName() {
return userName;
} /**
* @hibernate.property name="total" column="Total" type="double" not-null="false" unique="false"
*
* @return double
*/
public double getTotal() {
return total;
} /**
* @param i
*/
public void setId(String i) {
id = i;
} /**
* @param string
*/
public void setUserName(String string) {
userName = string;
} /**
* @param d
*/
public void setTotal(double d) {
total = d;
} /**
* @param set
*/
public void setOrderLineItems(Set set) {
orderLineItems = set;
}}
-----------------------------------------------------------------------
OrderLineItem.java
/*
* Created on Mar 5, 2004
*
* (c) 2004, Mark Eagle, [email protected]
* relased under terms of the GNU public license
* http://www.gnu.org/licenses/licenses.html#TOCGPL
*/
package com.meagle.bo;/**
* Simple order line item representation
*
* @hibernate.class table="OrderLineItem"
*
* @author meagle
*/
public class OrderLineItem {

private String id;

private double lineItemPrice;

private String description;

private Order order; /**
* Default constructor
*/
public OrderLineItem() {
super();
} /**
* Note: unsaved-value An identifier property value that indicates that an instance
* is newly instantiated (unsaved), distinguishing it from transient instances that
* were saved or loaded in a previous session.  If not specified you will get an exception like this:
* another object associated with the session has the same identifier
*
* @hibernate.id generator-class="native" type="int" column="OrderLineItem_ID" unsaved-value="0"
* @return int
*/
public String getId() {
return id;
}

/**
* @hibernate.many-to-one column="Order_ID" class="com.meagle.bo.Order"
*
* @return Order
*
*/
public Order getOrder() {
return order;
} /**
* @hibernate.property name="description" column="Description" type="string" not-null="false" unique="false"
*
* @return String
*/
public String getDescription() {
return description;
} /**
* @hibernate.property name="lineItemPrice" column="LineItemPrice" type="double" not-null="false" unique="false"
*
* @return double
*/
public double getLineItemPrice() {
return lineItemPrice;
} /**
* @param string
*/
public void setDescription(String string) {
description = string;
} /**
* @param i
*/
public void setId(String i) {
id = i;
} /**
* @param d
*/
public void setLineItemPrice(double d) {
lineItemPrice = d;
} /**
* @param order
*/
public void setOrder(Order order) {
this.order = order;
}}

Order.hbm.xml
<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd"><hibernate-mapping>
    <class
        name="com.meagle.bo.Order"
        table="Orders"
        dynamic-update="false"
        dynamic-insert="false"
    >        <id
            name="id"
            column="Order_ID"
            type="String"
            unsaved-value="0"
        >
            <generator class="uuid.hex">
            </generator>
        </id>        <set
            name="orderLineItems"
            table="OrderLineItem"
            lazy="true"
            inverse="true"
            cascade="save-update"
            sort="unsorted"
        >              <key
                  column="Order_ID"
              />              <one-to-many
                  class="com.meagle.bo.OrderLineItem"
              />
        </set>        <property
            name="userName"
            type="string"
            update="true"
            insert="true"
            column="UserName"
            not-null="true"
            unique="false"
        />        <property
            name="total"
            type="double"
            update="true"
            insert="true"
            column="Total"
            not-null="false"
            unique="false"
        />            </class></hibernate-mapping>
-----------------------------------------------------------------------
OrderLineItem.hbm.xml
<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd"><hibernate-mapping>
    <class
        name="com.meagle.bo.OrderLineItem"
        table="OrderLineItem"
        dynamic-update="false"
        dynamic-insert="false"
    >        <id
            name="id"
            column="OrderLineItem_ID"
            type="String"
            unsaved-value="0"
        >
            <generator class="uuid.hex">
            </generator>
        </id>        <many-to-one
            name="order"
            class="com.meagle.bo.Order"
            cascade="none"
            outer-join="auto"
            update="true"
            insert="true"
            column="Order_ID"
        />        <property
            name="description"
            type="string"
            update="true"
            insert="true"
            column="Description"
            not-null="false"
            unique="false"
        />        <property
            name="lineItemPrice"
            type="double"
            update="true"
            insert="true"
            column="LineItemPrice"
            not-null="false"
            unique="false"
        />            </class></hibernate-mapping>

据我了解,hibernate在一对多时是会出现一些问题.

ora 02289
*Cause: The specified sequence does not exist, or the user does
not have the required privilege to perform this operation.
*Action: Make sure the sequence name is correct, and that you have
the right to perform the desired operation on this sequence.检查一下用户是不是有权限使用这个sequence。
用sysdba连上后 select * from dba_sequences where SEQUENCE_NAME='序列名称' 看看有没有这个sequence

把unsaved-value="0"
改成
unsaved-value=null
看看

请问（神天月晓），如何才能用SQL/PLUS把这个unsaved-value=null写如到数据库呀？

调试易

100分求助:hibernate操作Oracle的时候主键的问题.

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