使用ORM工具时，您需要考虑Java对象。
根据您的问题，我认为您要编写的查询看起来像：
public List<Category> getCategoryList(int id) {
List<Category> groupList;
Session session = sessionFactory.getCurrentSession();
Query query = session.createQuery("select c from Category c join fetch c.events where c.parentCategory.categoryId = 1");
//query.setParameter("id", id);
groupList = query.list();
return groupList;
}
为此，您需要按如下所示更新类模型：
import java.io.Serializable;
import java.util.Date;
import javax.persistence.*;
@Entity
@Table(name = "events")
public class Event implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "event_id")
private int eventId;
@Column(name = "event_name")
private String eventName;
@Column(name = "event_description")
private String eventDescription;
@ManyToOne
@JoinColumn(name = "category_i")
private Category category;
@Column(name = "is_trending_event")
private Integer isTrendingEvent;
@Column(name = "image_url")
private String imageUrl;
private Integer status;
@Column(name = "created_date")
@Temporal(javax.persistence.TemporalType.DATE)
private Date createdDate;
@Column(name = "last_updated_date")
@Temporal(javax.persistence.TemporalType.DATE)
private Date lastUpdatedDate;
...
}
和
import java.io.Serializable;
import java.util.Date;
import javax.persistence.*;
@Entity
@Table(name = "category")
public class Category implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "category_id")
private int categoryId;
@Column(name = "category_name")
private String categoryName;
@ManyToOne
@JoinColumn(name="parent_category_id")
private Category parentCategory;
@Column(name = "created_date")
@Temporal(javax.persistence.TemporalType.DATE)
private Date createdDate;
@Column(name = "last_updated_date")
@Temporal(javax.persistence.TemporalType.DATE)
private Date lastUpdatedDate;
@OneToMany(mappedBy="category")
private List<Event> events;
...
}
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