[英]Spring Boot JPA custom Query with OneToMany
我正在Spring Boot中构建一个类似Twitter的应用程序。 我正在尝试为用户生成时间轴。 我对此进行了自定义查询,并将其添加到扩展CrudRepository<Account, Long>
repository
中。 当我尝试启动应用程序时,出现以下异常:
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: account_following is not mapped
该account_following表是@OneToMany
从Account
到Account
,你可以在下面的代码中看到。 我不确定如何将account_following
放入查询中。
AccountRepository.java
@Repository
public interface AccountRepository extends CrudRepository<Account, Long> {
@Query("SELECT t FROM Tweet t, account_following k WHERE k.following_id = t.owner_id AND k.account_ID = :account_ID AND k.following_id IN (SELECT following_ID FROM account_following WHERE account_id = :account_ID) ORDER BY unixdate DESC")
public List<Tweet> generateTimeline(@Param("account_ID") Long account_ID);
}
Account.java
@Entity
public class Account implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
@Column(unique=true)
private String username;
@Transient
private String password;
private String location;
private String description;
private String website;
@OneToMany(cascade = CascadeType.ALL)
private List<Account> following;
@OneToMany(mappedBy = "owner", cascade = CascadeType.ALL)
private List<Tweet> tweets;
}
Pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>kwetter</artifactId>
<groupId>org.springframework</groupId>
<version>0.1.0</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
</parent>
<dependencies>
<!--Spring Boot-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<type>jar</type>
</dependency>
<!--JAVAX-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<type>jar</type>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
<type>jar</type>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>5.0.8.RELEASE</version>
<scope>test</scope>
<type>jar</type>
</dependency>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>7.0</version>
<type>jar</type>
</dependency>
<!--DB-->
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>eclipselink</artifactId>
<version>2.5.2</version>
</dependency>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>org.eclipse.persistence.jpa.modelgen.processor</artifactId>
<version>2.5.2</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
</dependencies>
<properties>
<java.version>1.8</java.version>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
如下表所示,表account_following
存在于数据库中。 我正在使用MySQL version 8.0.12
。
尝试将查询更改为本机查询。
@Repository
public interface AccountRepository extends CrudRepository<Account, Long> {
@Query(value= "SELECT t FROM Tweet t, account_following k WHERE k.following_id = t.owner_id AND k.account_ID = :account_ID AND k.following_id IN (SELECT following_ID FROM account_following WHERE account_id = :account_ID) ORDER BY unixdate DESC",nativeQuery=true)
public List<Tweet> generateTimeline(@Param("account_ID") Long account_ID);
}
由于没有名为account_following的实体,因此您会在HQL中得到该错误。
如果是JPQL:
SELECT t FROM Tweet as t, Account as account WHERE account.following as f on f.id = t.ownerId ...
请注意,以上字段必须与类字段相同,而不是数据库中的列名。
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