休眠：无法使用外键查询数据库表答案

【问题标题】：Hibernate: Unable to query a database table using a Foreign Key休眠：无法使用外键查询数据库表
【发布时间】：2021-01-15 19:44:22
【问题描述】：

我正在尝试烧毁下面的 Hibernare 采石场。

 Query query = session.createSQLQuery("from Rating as rating where rating.organization.idorganization = :idorganization");

我总是以错误告终

hibernate.engine.jdbc.spi.SqlExceptionHelper.logExceptions You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'from Rating as rating where rating.organization.idorganization = 65' at line 1
org.hibernate.exception.SQLGrammarException: could not extract ResultSet

下面是我的Rating豆

public class Rating  implements java.io.Serializable {


     private Integer idrating;
     private Organization organization;
     private User user;
     private double rating;
     private Date dateCreated;
     private Date lastUpdated;

    public Rating() {
    }

    
    public Rating(Organization organization, User user, double rating) {
        this.organization = organization;
        this.user = user;
        this.rating = rating;
    }
    public Rating(Organization organization, User user, double rating, Date dateCreated, Date lastUpdated) {
       this.organization = organization;
       this.user = user;
       this.rating = rating;
       this.dateCreated = dateCreated;
       this.lastUpdated = lastUpdated;
    }
   
    public Integer getIdrating() {
        return this.idrating;
    }
    
    public void setIdrating(Integer idrating) {
        this.idrating = idrating;
    }
    public Organization getOrganization() {
        return this.organization;
    }
    
    public void setOrganization(Organization organization) {
        this.organization = organization;
    }
    public User getUser() {
        return this.user;
    }
    
    public void setUser(User user) {
        this.user = user;
    }
    public double getRating() {
        return this.rating;
    }
    
    public void setRating(double rating) {
        this.rating = rating;
    }
    public Date getDateCreated() {
        return this.dateCreated;
    }
    
    public void setDateCreated(Date dateCreated) {
        this.dateCreated = dateCreated;
    }
    public Date getLastUpdated() {
        return this.lastUpdated;
    }
    
    public void setLastUpdated(Date lastUpdated) {
        this.lastUpdated = lastUpdated;
    }


}

下面是Rating.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- Generated Sep 19, 2020 8:15:23 PM by Hibernate Tools 4.3.1 -->
<hibernate-mapping>
    <class name="beans.Rating" table="rating" catalog="autocircle" optimistic-lock="version">
        <id name="idrating" type="java.lang.Integer">
            <column name="idrating" />
            <generator class="identity" />
        </id>
        <many-to-one name="organization" class="beans.Organization" fetch="select">
            <column name="idorganization" not-null="true" />
        </many-to-one>
        <many-to-one name="user" class="beans.User" fetch="select">
            <column name="iduser" not-null="true" />
        </many-to-one>
        <property name="rating" type="double">
            <column name="rating" precision="22" scale="0" not-null="true" />
        </property>
        <property name="dateCreated" type="timestamp">
            <column name="date_created" length="0" />
        </property>
        <property name="lastUpdated" type="timestamp">
            <column name="last_updated" length="0" />
        </property>
    </class>
</hibernate-mapping>

为什么会出现这个错误？

【问题讨论】：

查询不应该从“Select * from..”开始吗？
@edison16029：你发现了错误！当我想使用 HQL 时，我正在使用 SQL Quary。所以我应该使用session.createQuery。请提供这个作为答案，我会批准它。
@LemonJuice 顺便说一下，hibernate 不鼓励没有选择原因的做法。请参阅documentation：尽管 HQL 不需要存在 select_clause，但通常最好包含一个。
@SternK 当然。我会将它添加到 HQL 中

标签： java mysql database hibernate hibernate-mapping

【解决方案1】：

由于您使用的是 createSQLQuery 方法，因此应使用 SQL 语句。在这种情况下，应该是

"select * from Rating as rating where rating.organization.idorganization = :idorganization"

或使用 HQL 方法和适当的 HQL 查询

【讨论】：