Question

将Google App Engine与MySQL结合使用

JPA忽略了我的列别名

我试过声明变量：

@Column(name = "fk_location_id") 
private Long locationId;

我也试过在getter上声明：

@Column(name = "fk_location_id") 
public Long getLocationId() {
    return locationId;
}

我也尝试过宣布

没有工作。只是抛出错误：

Caused by: org.datanucleus.store.rdbms.exceptions.MissingColumnException: Required columns missing from table fk_location_id

我已经google了一下，找到了与Hibernate相关的内容，但不相信我正在使用它？

这是我的persistence.xml文件

<property name="datanucleus.ConnectionDriverName" value="com.mysql.jdbc.Driver" />
<property name="datanucleus.ConnectionURL" value="jdbc://mydb..." />
<property name="datanucleus.ConnectionUserName" value="user" />
<property name="datanucleus.ConnectionPassword" value="pass" />
<property name="datanucleus.autoStartMechanism" value="None" />
<property name="datanucleus.validateTables" value="true" />
<property name="datanucleus.validateConstraints" value="true" />
<property name="datanucleus.validateColumns" value="true" />
<property name="datanucleus.DetachAllOnCommit" value="true" />
<property name="datanucleus.maxFetchDepth" value="1" />
<property name="datanucleus.storeManagerType" value="rdbms" />

以下是表格的架构：

CREATE TABLE `sites` (
`id` int NOT NULL AUTO_INCREMENT,
`name` varchar(255) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
`fk_location_id` bigint(20) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;

我如何查询数据库：

EntityManagerFactory factory;
factory = Persistence.createEntityManagerFactory(Globals.PERSISTENCE_UNIT_NAME);
EntityManager em = factory.createEntityManager();

Query q = em.createQuery("select t from Site t");
List<Site> siteList = q.getResultList();

Java类：

@Entity
@Table(name = "sites")
public class Site {

private Long id;
private String name;
private Long locationId;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}


public Long getLocationId() {
    return locationId;
}

public void setLocationId(Long locationId) {
    this.locationId = locationId;
}

}

错误告诉FKLOCATIONID列未找到，因此当它应该搜索fk_location_id时搜索FKLOCATIONID

Answer 1

确保@Column注释来自javax.persistence，而不是来自JDO或其他地方。 DataNucleus只能使用JDO或JPA注释，但不能同时使用两者

@Column名称忽略了JPA

1 个答案: