我很抱歉我的问题可能很愚蠢。我有产品和订单表(具有多对多关系),还有一个用户表。现在我想通过 user_id 和特殊字段“order_satus”获取产品数量。我可以让两个查询按特殊条件获取订单,然后按顺序获取产品的大小。但这根本不是最佳的。当我使用 JDBCTemplate 时,我进行了很多连接,但只得到一个查询。
这是我的实体:
@Entity
@Table(name = "shop.order")
public class Order {
@Id
@Column(name = "order_id")
@GeneratedValue(strategy = GenerationType.AUTO)
private long orderId;
private long user_id;
@Column(name = "databegin")
private Date dateBegin;
@Column(name = "dataend")
private Date dateEnd;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id", insertable = false, updatable = false)
private User user;
@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(name = "order_product", joinColumns = { @JoinColumn(name = "order_id") }, inverseJoinColumns = { @JoinColumn(name = "product_id") })
private List<Product> products;
}
产品实体
@Entity
@Table(name = "product")
public class Product {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int product_id;
@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(name = "order_product", joinColumns = { @JoinColumn(name = "product_id") }, inverseJoinColumns = { @JoinColumn(name = "order_id") })
private List<Order> order;
public List<Order> getOrder() {
return order;
}
public void setOrder(List<Order> order) {
this.order = order;
}
@Column
@NotBlank
private String name;
@Column
@Max(value = 250)
private String descr;
@Column
@Max(value = 250)
private String manufacturer;
@Column
private Double price;
@Column
private Byte[] barcode;
@Column
private Byte[] picture;
@ForeignKey(name = "category_id")
private int category_id;
最佳答案
当你给出sql查询时..
'select count(*) from produtc p join order ord on ord.id = ? and ord.status = ?' – Igor Masternoy
根据您提供的实体结构,HQL 将是..
select ord.products productList from Order ord where ord.id=? and ord.status=?
此查询将返回产品列表 ( List<Product> products
),然后您可以通过 java 代码获取计数,即 productList.size();
此尺寸是您需要的产品数量,基于您将作为参数传递的订单 ID 和订单状态,您也可以附加 user.id
在哪里导致根据用户过滤您的结果。
这是根据您的需要的产品列表..
Query query = getSession().createQuery("select ord.products productList from Order ord where ord.id=:orderID and ord.status=:orderStatus");
query.setInteger("orderID", orderIDParameter);
query.setString("orderStatus", orderStatusParameter);
List<Product> productList = (List<Product>) query.list();
Integer productCount = productList.size();
此productCount是您需要的产品数量。
关于java - hibernate 查询,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10913677/