Hibernate HQL多对一连接

Question

我在mysql中有2个表， blocked_histories和blocked_detail_histories 。 block_detail_histories表与block_histories具有多对一的休眠关系。 表创建脚本如下所示

历史记录

CREATE TABLE `blocked_histories` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `type` VARCHAR(32) NOT NULL,
  `no_ecash` varchar(13) NOT NULL,
  `cif` VARCHAR(32) DEFAULT NULL,
  `reason_id` INT(4) NOT NULL,
  `desc` TEXT,
  `status` VARCHAR(32) NOT NULL,
  `created_date` DATETIME NOT NULL,
  `created_by` VARCHAR(100) NOT NULL,
  `total_balance` DECIMAL(15,6) NOT NULL,
  `broker` int(11) NOT NULL,
  `blocked_id` INT(11) NOT NULL UNIQUE,
  `remark` text,
  PRIMARY KEY (`id`),
    CONSTRAINT `CUSTOMFIELD_ID_FK` FOREIGN KEY (`reason_id`) REFERENCES `custom_field_possible_values` (`id`)
)  ENGINE=INNODB AUTO_INCREMENT=312 DEFAULT CHARSET=latin1;

block_detail_histories

CREATE TABLE `blocked_detail_histories` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `blocked_id` INT(11) NOT NULL,
  `no_ecash` VARCHAR(13) DEFAULT NULL,
  `prev_group` INT(11) NOT NULL,
  `balance` DECIMAL(15,6) NOT NULL,
  PRIMARY KEY (`id`),
   KEY `BLOCKED_ID_FK` (`blocked_id`),
   CONSTRAINT `BLOCKED_ID_HISTORIES_FK` FOREIGN KEY (`blocked_id`) REFERENCES `blocked_histories` (`blocked_id`)
)  ENGINE=INNODB AUTO_INCREMENT=312 DEFAULT CHARSET=latin1;

休眠映射看起来像这样

历史记录

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

    <class dynamic-insert="true" dynamic-update="true"
        name="nl.strohalm.cyclos.entities.groups.BlockedHistories"
        table="blocked_histories">
        <id name="id" type="long">
            <column name="id" sql-type="bigint" />
            <generator class="native" />
        </id>
        <property name="type" column="type" type="string" not-null="true" length="32" />
        <property name="noEcash" column="no_ecash" type="string" not-null="true" length="13" />
        <property name="cif" column="cif" type="string" length="32" />

        <!--  <property name="reasonId" column="reason_id" type="int" not-null="true" length="11" /> -->
        <many-to-one name="reasonId" class="nl.strohalm.cyclos.entities.customization.fields.CustomFieldPossibleValue">
            <column name="reason_id" sql-type="integer"></column>
        </many-to-one>

        <property name="desc" column="desc" type="text" not-null="true" />
        <property name="status" column="status" type="string" length="32" />
        <property name="createdDate" column="created_date" type="calendar" not-null="true" />
        <property name="createdBy" column="created_by" type="string" not-null="true" length="100"/>
        <property name="totalBalance" column="total_balance" type="big_decimal" not-null="true" precision="15" scale="6" />
        <property name="brokerId" column="broker" type="int" not-null="true" length="11" />
        <property name="remark" column="remark" type="text" />
        <property name="blockedId" column="blocked_id" type="int" not-null="true" length="11" />
    </class>

</hibernate-mapping>

block_detail_histories

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

    <class dynamic-insert="true" dynamic-update="true"
        name="nl.strohalm.cyclos.entities.groups.BlockedDetailHistories"
        table="blocked_detail_histories">
        <id name="id" type="long">
            <column name="id" sql-type="bigint" />
            <generator class="native" />
        </id>
        <many-to-one name="blockedHistories" class="nl.strohalm.cyclos.entities.groups.BlockedHistories">
            <column name="blocked_id" sql-type="integer"></column>
        </many-to-one>
        <property name="noEcash" column="no_ecash" type="string" not-null="true" length="13" />
        <property name="prevGroup" column="prev_group" type="int" not-null="true" length="11" />
        <property name="balance" column="balance" type="big_decimal" not-null="true" precision="15" scale="6" />
    </class>

</hibernate-mapping>

如您所见，blocked_detail histories表与blocked_histories表具有多对一关系（在“ blockedHistories”列中）

我试图运行一个简单的mysql查询来连接看起来像这样的两个表

select bh.created_date, bdh.no_ecash, bh.type,
    bh.cif, bh.desc, bh.reason_id,
    bh.status, bh.created_by, bh.remark
from blocked_detail_histories bdh
join blocked_histories bh 
where bdh.blocked_id=4;

上面的mysql查询工作正常，但是当我尝试将上面的mysql查询转换为HQL查询时，结果什么也没有给我。HQL看起来像这样（“：id”在这里是Java NamedParameters）

select bdh.blockedHistories.blockedId
from BlockedDetailHistories bdh"
join bdh.blockedHistories bh
where bh.blockedId = :id

我尝试了这个，但是也没有给我任何东西

select bh.createdDate, bdh.noEcash, bh.type,
bh.cif, bh.desc, bh.reasonId,
bh.status, bh.createdBy, bh.remark
from BlockedDetailHistories bdh
join bdh.blockedHistories bh
where bh.blockedId = :id

任何建议，我在这里想念什么？ 关系定义呢？ 还是其他？ 任何帮助将不胜感激 ：）

Answer 1

不是xml休眠映射的专家，但是您是否为休眠实体类应用了提取类型，如果您定义了这种类型，则可以按以下方式在查询中重试（对于延迟提取类型）

select bdh.blockedHistories.blockedId
from BlockedDetailHistories bdh
left join fetch bdh.blockedHistories bh
where bh.blockedId = :id