change from many to many to one to many for cart product

kbazaar/src/main/java/com/kampus/kbazaar/cart/Cart.java

@@ -1,6 +1,5 @@
 package com.kampus.kbazaar.cart;
 
-import com.kampus.kbazaar.product.Product;
 import com.kampus.kbazaar.promotion.Promotion;
 import com.kampus.kbazaar.shopper.Shopper;
 import jakarta.persistence.*;
@@ -21,12 +20,8 @@ public class Cart {
     @Column(name = "id")
     private Long id;
 
-    @ManyToMany(cascade = {CascadeType.ALL})
-    @JoinTable(
-            name = "cart_product",
-            joinColumns = @JoinColumn(name = "cart_id"),
-            inverseJoinColumns = @JoinColumn(name = "product_id"))
-    private Set<Product> products;
+    @OneToMany(mappedBy = "cart", cascade = CascadeType.ALL)
+    private Set<CartProduct> products;
 
     @ManyToMany(cascade = {CascadeType.ALL})
     @JoinTable(
@@ -39,9 +34,9 @@ public class Cart {
     @JoinColumn(name = "shopper_id", referencedColumnName = "id")
     private Shopper shopper;
 
-    public Cart addProduct(Product product) {
-        this.products.add(product);
-        product.getCarts().add(this);
+    public Cart addPromotion(Promotion promotion) {
+        this.promotions.add(promotion);
+        promotion.getCarts().add(this);
         return this;
     }
 }

kbazaar/src/main/java/com/kampus/kbazaar/cart/CartProduct.java

@@ -0,0 +1,27 @@
+package com.kampus.kbazaar.cart;
+
+import jakarta.persistence.*;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class CartProduct {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "id")
+    private Long id;
+
+    @Column(name = "product_id")
+    private Long productId;
+
+    @Column(name = "quantity")
+    private Integer quantity;
+
+    @ManyToOne
+    @JoinColumn(name = "cart_id")
+    private Cart cart;
+}

kbazaar/src/main/java/com/kampus/kbazaar/product/Product.java

@@ -1,13 +1,11 @@
 package com.kampus.kbazaar.product;
 
-import com.kampus.kbazaar.cart.Cart;
 import jakarta.persistence.*;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.NotNull;
 import jakarta.validation.constraints.PositiveOrZero;
 import jakarta.validation.constraints.Size;
 import java.math.BigDecimal;
-import java.util.Set;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -27,11 +25,6 @@ public class Product {
     @Column(name = "id")
     private Long id;
 
-    @ManyToMany(
-            cascade = {CascadeType.ALL},
-            mappedBy = "products")
-    private Set<Cart> carts;
-
     @NotBlank
     @Size(max = 255)
     @Column(name = "name", nullable = false, length = 255)