Question

我有两个类Task和TaskComponents。 TaskComponents包含由Task_ID映射的任务。我正在尝试选择加入TaskComponents表的任务。我已经尝试了许多不同的SQL语句，但是所有这些语句都返回QuerySyntaxException Path Expected to join。

任务POJO

@Entity
@Table(name = "task")
public class Task implements Serializable {

@Id
@Column(name = "ID")
private int Id;

@Column(name = "Name")
private String name;

@Column(name = "Description")
private String description;

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "Site_ID")
private Site site;

public int getId() {
    return Id;
}

public void setId(int Id) {
    this.Id = Id;
}

public String getName() {
    return name;
}

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

public String getDescription() {
    return description;
}

public void setDescription(String description) {
    this.description = description;
}

public Site getSite() {
    return site;
}

public void setSite(Site site) {
    this.site = site;
}


}

TaskComponents POJO

@Entity
@Table(name = "taskcomponents")
public class TaskComponents implements Serializable {

@Id
@Column(name = "ID")
private int Id;

@Column(name = "VersionName")
private String versionName;

@Column(name = "Live", nullable = false)
@Type(type = "org.hibernate.type.NumericBooleanType")
private boolean live;

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "Task_ID")
private Task task;

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "Group_ID")
private GroupDB group;

public int getId() {
    return Id;
}

public void setId(int Id) {
    this.Id = Id;
}

public String getVersionName() {
    return versionName;
}

public void setVersionName(String versionName) {
    this.versionName = versionName;
}

public boolean isLive() {
    return live;
}

public void setLive(boolean live) {
    this.live = live;
}

public Task getTask() {
    return task;
}

public void setTask(Task task) {
    this.task = task;
}

public GroupDB getGroup() {
    return group;
}

public void setGroup(GroupDB group) {
    this.group = group;
}
}

我试图查询。

Query query = session.createQuery("SELECT t FROM Task t INNER JOIN TaskComponents tc ON t.Id=tc.task.Id");

Query query = session.createQuery("SELECT t FROM Task t INNER JOIN TaskComponents tc ON t=tc.task");

Answer 1

你不应该使用explicitely ON来定义连接，Hibernate会从映射推断它，只需将你的查询写成

SELECT tc.task FROM TaskComponents tc INNER JOIN tc.task

这是您的错误消息Path expected for join后面引用的内容，查询期望从一个实体到另一个实体的属性定义路径

INNER JOIN使用hibernate

1 个答案: