[英]Executing the NOT IN QUERY for objects with Many to Many relationships in JPA
我有两个JPA对象,即“ Product
和“ Order
,它们彼此之间具有多对多的关系。
@Entity
@Table(name = "orders")
@JsonInclude(NON_NULL)
public class Order implements Serializable {
public static final int PRECISION = 2;
@Id
@GeneratedValue(strategy = IDENTITY)
@JsonIgnore
private String orderId;
@Column(unique = true, nullable = false, length = 8)
private String orderNumber;
@Column
private BigDecimal discount;
@Column(nullable = false)
private BigDecimal taxPercent;
private BigDecimal total;
private BigDecimal totalTax;
private BigDecimal grandTotal;
@Column(length = 10)
private String status;
@ManyToMany(cascade = ALL, fetch = FetchType.EAGER)
@JoinTable(
name = "order_product",
joinColumns = @JoinColumn(name = "order_id", updatable = false, nullable = false),
inverseJoinColumns = @JoinColumn(name = "product_id", updatable = false, nullable = false)
)
private List<Product> products = new ArrayList<>();
public BigDecimal getTotal() {
BigDecimal total = new BigDecimal(ZERO);
if (products == null || products.isEmpty()) {
return total;
}
for (Product product : products) {
total = total.add(product.getPrice());
}
return scaled(total);
}
public BigDecimal getTotalTax() {
return scaled(getTotal().multiply(taxPercent.divide(new BigDecimal("100"))));
}
public BigDecimal getGrandTotal() {
BigDecimal total = this.getTotal().add(getTotalTax());
if (discount != null) {
return scaled(total.subtract(discount));
}
return scaled(total);
}
private BigDecimal scaled(BigDecimal value) {
return value.setScale(PRECISION, ROUND_FLOOR);
}
.. Getters and setters ...
}
和产品
@Entity
@Table(name = "products")
public class Product implements Serializable {
@Id
@GeneratedValue(strategy = IDENTITY)
@JsonIgnore
private String productId;
@Column(unique = true, nullable = false, length = 10)
private String upc;
@Column(unique = true, nullable = false, length = 13)
private String sku;
@Column(nullable = false)
private String description;
@Column(nullable = false)
private BigDecimal price;
public BigDecimal getPrice() {
return price;
}
@ManyToMany(mappedBy="products", fetch=FetchType.EAGER)
@JsonIgnore
private List<Order> orders = new ArrayList<>();
// Getters and setters.
}
这是我的DML
insert into products (product_id, upc, sku, description, price) values ('1', '1257833283', '9394550220002', 'Diva Jeans', 39.99);
insert into products (product_id, upc, sku, description, price) values ('2', '1358743283', '7394650110003', 'Polo Shirt', 19.99);
insert into products (product_id, upc, sku, description, price) values ('3', '1458843283', '7394750120000', 'Floral Swing Skirt', 69.99);
insert into products (product_id, upc, sku, description, price) values ('4', '1358753283', '7394850130001', 'Denim Short', 29.99);
insert into products (product_id, upc, sku, description, price) values ('5', '1258793283', '7394950140000', 'True Skinny Jeans', 49.99);
insert into orders (order_id, order_number, tax_percent, status) values ('1', 'RTL_1001', 10, 'SHIPPED');
insert into orders (order_id, order_number, discount, tax_percent, status) values ('2', 'RTL_1002', 15.55, 10, 'FULFILLED');
insert into order_product (order_id, product_id) values ('1', '1');
insert into order_product (order_id, product_id) values ('1', '2');
insert into order_product (order_id, product_id) values ('2', '2');
我只想选择那些产品
如果我按不存在的订单查询产品(例如,order_id = 3则不存在),我想返回所有符合条件的产品,因为尚未创建订单。
如果我按确实存在的订单查询产品,那么我希望数据库返回不与该订单关联的所有产品。 例如,对于order_id = 1
,我希望返回id = 3、4和5的产品。 由于order_id = 1已与product_id = 1和2关联,因此我不希望这些产品退回。
如果我要编写JDBC SQL查询
SELECT p.product_id
FROM Product p
WHERE NOT EXISTS
(
SELECT 1
FROM order_product
WHERE product_id = p.product_id
AND
order_id = ?
)
OR
NOT EXISTS
(
SELECT 1
FROM order_product
WHERE order_id = ?
)
我不知道如何使用JPA创建类似的查询。 我所能想到的就是这样。
创建一个从JPARepository继承的ProductRepository
从产品表中获取所有产品,包括order_product表中的产品。
使用JPA提取给定订单ID的产品,并从(2)中的产品中删除该产品
我希望有一个更好的方法。
Order order = em.getReference(Order.class, orderId);
em.createQuery("select distinct p from Product p where :order not member of p.orders")...;
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