Hibernate之HQL左关联配置

Hibernate之HQL左关联配置

一般在单表中查询,hql类似于SQL的写法 不过是把字段变成属性名。当两个表关联查询的时候,一般联合查询也不会有问题。当如果需要左关联的时候，HQL就不能直接实现了，必须要配置主从表的关系才能够成功的实现SQL中的左关联！

现在有一个需求：

供应商表Supplier 与报名表ItemEnroll

现在有一个报名的功能,如果需要供应商登陆，我就会在ItemEnroll中用participateId字段 记录供应商的supplierId。如果不需要登陆，就要把participateId字段放空。

我现在需要做一个查询页面，查询报名的信息以及供应商的supplierName。这个时候 我需要用一句HQL实现。假设participateId字段为空，全关联ItemEnroll，Supplier表的时候，没有供应商信息的报名也不会查询来。

我需要的效果是无论有没有供应商的信息，有一条报名信息 就要查出来一条报名信息。这个时候就需要左关联的写法。需要配置XML的文件。中间经历了一些曲折，最后把配出的结果与几点经验教训贴出来。

1. 当写左关联的时候，需要在配置文件中配置一对多或者多对一的关系。

2. HQL写左关联的时候,ON条件省略。在配置文件中配置。

3. 分析好是多对一还是一对多的关系。

4. 多对一或者一对多中配置的COLUMN属性都是指子表中记录的那个关联的外键！

关键的几句代码:

  <property
        name="participateId"
        type="java.lang.Long"
        column="participate_id"
   />
    
  <many-to-one name="supplier" class="com.dfe.bcm.po.DfSupplierPO" cascade="none" insert="false" update="false">
   <column name="participate_id" ></column>
  </many-to-one>

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

以下为可看可不看的信息。供记忆！

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

Supplier供应商表:

HQL配置文件与JAVABEAN代码:

报名：

<?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.dfe.bcm.po.DfItemEnrollPO"
    table="DF_ITEM_ENROLL"
>

    <id
        name="itenId"
        type="java.lang.Long"
        column="iten_id"
    >
        <generator class="native" />
    </id>

     <property
        name="itemIdentifying"
        type="java.lang.Long"
        column="item_Identifying"
    />

    <property
        name="itemName"
        type="java.lang.String"
        column="ITEM_NAME"

    />



   <property
        name="participateRemark"
        type="java.lang.String"
        column="participate_Remark"
    />

  <property
        name="enrollTime"
        type="java.sql.Date"
        column="enroll_Time"
    />

  <property
        name="enrollRemark"
        type="java.lang.String"
        column="enroll_Remark"
    />

  <property
        name="enrollReturnCode"
        type="java.lang.String"
        column="enroll_Return_Code"
    />

    <property
        name="enrollAuditStatus"
        type="java.lang.String"
        column="enroll_Audit_Status"
    />

  <property
        name="siteId"
        type="java.lang.String"
        column="site_id"
    />

 <property
        name="domainId"
        type="java.lang.String"
        column="domain_id"
    />

<property
        name="createTime"
        type="java.sql.Timestamp"
        column="create_time"
   />

<property
        name="creator"
        type="java.lang.String"
        column="creator"
   />

<property
        name="updateTime"
        type="java.sql.Timestamp"
        column="update_time"
    />

 <property
        name="updator"
        type="java.lang.String"
        column="updator"
   />

  <property
        name="participateId"
        type="java.lang.Long"
        column="participate_id"
   />
    
  
  <many-to-one name="supplier" class="com.dfe.bcm.po.DfSupplierPO" insert="false" update="false">
   <column name="participate_id" ></column>
  </many-to-one>


</class>
</hibernate-mapping>

package com.dfe.bcm.po;

import java.util.Date;
import java.util.Set;
import java.util.HashSet;


/**
 * 项目报名
 * @version 1.0
 */
public class DfItemEnrollPO {
    private Long itenId;
    private Long itemIdentifying; //项目的ID 采购需求/库存分享的ID
    private String itemName;
    private Long participateId; //参与者ID 比如供应商的ID或者参与网上竞价的ID
    private String participateRemark;
    private Date enrollTime; //报名时间
    private String enrollRemark;
    private String enrollReturnCode;
    private String enrollAuditStatus;
    private String siteId;
    private String domainId;
    private Date createTime;
    private String creator;
    private Date updateTime;
    private String updator;
    private DfSupplierPO supplier;

    public String getEnrollReturnCode() {
        return enrollReturnCode;
    }

    public String getParticipateRemark() {
        return participateRemark;
    }

    public String getEnrollRemark() {
        return enrollRemark;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public String getCreator() {
        return creator;
    }

    public String getUpdator() {
        return updator;
    }

    public String getDomainId() {
        return domainId;
    }

    public Date getEnrollTime() {
        return enrollTime;
    }

    public String getItemName() {
        return itemName;
    }

    public Long getItenId() {
        return itenId;
    }

    public String getSiteId() {
        return siteId;
    }

    public Long getItemIdentifying() {
        return itemIdentifying;
    }

    public Date getUpdateTime() {
        return updateTime;
    }

    public void setEnrollAuditStatus(String enrollAuditStatus) {
        this.enrollAuditStatus = enrollAuditStatus;
    }


    public void setEnrollReturnCode(String enrollReturnCode) {
        this.enrollReturnCode = enrollReturnCode;
    }

    public void setParticipateRemark(String participateRemark) {
        this.participateRemark = participateRemark;
    }

    public void setEnrollRemark(String enrollRemark) {
        this.enrollRemark = enrollRemark;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public void setCreator(String creator) {
        this.creator = creator;
    }

    public void setUpdator(String updator) {
        this.updator = updator;
    }

    public void setDomainId(String domainId) {
        this.domainId = domainId;
    }

    public void setEnrollTime(Date enrollTime) {
        this.enrollTime = enrollTime;
    }

    public void setItemName(String itemName) {
        this.itemName = itemName;
    }

    public void setItenId(Long itenId) {
        this.itenId = itenId;
    }

    public void setSiteId(String siteId) {
        this.siteId = siteId;
    }

    public void setItemIdentifying(Long itemIdentifying) {
        this.itemIdentifying = itemIdentifying;
    }

    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }

    public void setParticipateId(Long participateId) {
        this.participateId = participateId;
    }

    public void setSupplier(DfSupplierPO supplier) {
        this.supplier = supplier;
    }


    public String getEnrollAuditStatus() {
        return enrollAuditStatus;
    }

    public Long getParticipateId() {
        return participateId;
    }

    public DfSupplierPO getSupplier() {
        return supplier;
    }


}

供应商:

<?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.dfe.bcm.po.DfSupplierPO"
    table="DF_SUPPLIER"
>

<id
        name="supplierId"
        type="java.lang.Long"
        column="supplier_id"
    >
        <generator class="native" />
    </id>


     <property
        name="supplierName"
        type="java.lang.String"
        column="supplier_name"
    />

    <property
        name="supplierAccount"
        type="java.lang.String"
        column="supplier_account"

    />

        <property
        name="remark"
        type="java.lang.String"
        column="remark"

    />

     <property
        name="groupId"
        type="java.lang.Long"
        column="group_Id"

    />

        <property
        name="siteId"
        type="java.lang.String"
        column="site_id"
    />

        <property
        name="domainId"
        type="java.lang.String"
        column="domain_id"
    />

    <property
        name="createTime"
        type="java.sql.Timestamp"
        column="create_time"
   />

    <property
        name="creator"
        type="java.lang.String"
        column="creator"
   />


    <property
        name="updateTime"
        type="java.sql.Timestamp"
        column="update_time"
    />

    <property
        name="updator"
        type="java.lang.String"
        column="updator"
   />

    <property
        name="supplierPassword"
        type="java.lang.String"
        column="supplier_Password"
    />

    <property
        name="approvalStatus"
        type="java.lang.String"
        column="approval_Status"
    />
    
    <!--AddAt2010-12-13 -->
<property
        name="companyName"
        type="java.lang.String"
        column="company_Name"
    />
    
<property
        name="address"
        type="java.lang.String"
        column="address"
    />
    
<property
        name="zipCode"
        type="java.lang.String"
        column="zip_Code"
    />
    
<property
        name="legalRepresentative"
        type="java.lang.String"
        column="legal_Representative"
    />
    
<property
        name="organizationCode"
        type="java.lang.String"
        column="organization_Code"
    />
    
<property
        name="businessLicenceNo"
        type="java.lang.String"
        column="business_Licence_No"
    />
    
<property
        name="registeredCapital"
        type="java.lang.String"
        column="registered_Capital"
    />
    
<property
        name="lineOfBusiness"
        type="java.lang.String"
        column="line_Of_Business"
    />
    
 <property
        name="webSite"
        type="java.lang.String"
        column="web_Site"
    />
    
<property
        name="telphone"
        type="java.lang.String"
        column="telphone"
    />
    
 <property
        name="fax"
        type="java.lang.String"
        column="fax"
    />
    
</class>
</hibernate-mapping>

package com.dfe.bcm.po;

import java.util.Date;


public class DfSupplierPO {

    private Long supplierId;
    private String supplierName;
    private String supplierAccount;
    private String remark;
    private Long groupId;


    //通用字段
    private String siteId;
    private String domainId;
    private Date createTime;
    private String creator;
    private Date updateTime;
    private String updator;


    //补充字段
    private String supplierPassword;
    private String approvalStatus;

    //AddAt2010-12-13
    private String companyName;//公司名称
    private String address;//地址
    private String zipCode;//邮政编码
    private String legalRepresentative;//法人代表
    private String organizationCode;//组织机构代码
    private String businessLicenceNo;//法人营业执照编号
    private String registeredCapital;//注册资金
    private String lineOfBusiness;//营业范围
    private String webSite;//公司网址
    private String telphone;//电话号码
    private String fax;//传真

    public String getRemark() {
        return remark;
    }

    public String getDomainId() {
        return domainId;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public String getSupplierName() {
        return supplierName;
    }

    public Long getSupplierId() {
        return supplierId;
    }

    public String getSiteId() {
        return siteId;
    }

    public String getSupplierAccount() {
        return supplierAccount;
    }

    public String getCreator() {
        return creator;
    }

    public Date getUpdateTime() {
        return updateTime;
    }

    public String getUpdator() {
        return updator;
    }

    public void setGroupId(Long groupId) {
        this.groupId = groupId;
    }

    public void setRemark(String remark) {
        this.remark = remark;
    }

    public void setDomainId(String domainId) {
        this.domainId = domainId;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public void setSupplierName(String supplierName) {
        this.supplierName = supplierName;
    }

    public void setSupplierId(Long supplierId) {
        this.supplierId = supplierId;
    }

    public void setSiteId(String siteId) {
        this.siteId = siteId;
    }

    public void setSupplierAccount(String supplierAccount) {
        this.supplierAccount = supplierAccount;
    }

    public void setCreator(String creator) {
        this.creator = creator;
    }

    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }

    public void setUpdator(String updator) {
        this.updator = updator;
    }

    public void setSupplierPassword(String supplierPassword) {
        this.supplierPassword = supplierPassword;
    }

    public void setApprovalStatus(String approvalStatus) {
        this.approvalStatus = approvalStatus;
    }

    public void setBusinessLicenceNo(String businessLicenceNo) {
        this.businessLicenceNo = businessLicenceNo;
    }

    public void setWebSite(String webSite) {
        this.webSite = webSite;
    }

    public void setZipCode(String zipCode) {
        this.zipCode = zipCode;
    }

    public void setOrganizationCode(String organizationCode) {
        this.organizationCode = organizationCode;
    }

    public void setCompanyName(String companyName) {
        this.companyName = companyName;
    }

    public void setFax(String fax) {
        this.fax = fax;
    }

    public void setLineOfBusiness(String lineOfBusiness) {
        this.lineOfBusiness = lineOfBusiness;
    }

    public void setTelphone(String telphone) {
        this.telphone = telphone;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public void setRegisteredCapital(String registeredCapital) {
        this.registeredCapital = registeredCapital;
    }

    public void setLegalRepresentative(String legalRepresentative) {
        this.legalRepresentative = legalRepresentative;
    }

    public Long getGroupId() {
        return groupId;
    }

    public String getSupplierPassword() {
        return supplierPassword;
    }

    public String getApprovalStatus() {
        return approvalStatus;
    }

    public String getBusinessLicenceNo() {
        return businessLicenceNo;
    }

    public String getWebSite() {
        return webSite;
    }

    public String getZipCode() {
        return zipCode;
    }

    public String getOrganizationCode() {
        return organizationCode;
    }

    public String getCompanyName() {
        return companyName;
    }

    public String getFax() {
        return fax;
    }

    public String getLineOfBusiness() {
        return lineOfBusiness;
    }

    public String getTelphone() {
        return telphone;
    }

    public String getAddress() {
        return address;
    }

    public String getRegisteredCapital() {
        return registeredCapital;
    }

    public String getLegalRepresentative() {
        return legalRepresentative;
    }


}

ItemEnroll报名表：