One to many assosiation using @Onetomany @JoinColumn in spring boot?

Question

I am beginner in spring boot and web development and trying to do one-to-many association mapping using Onetomany and joincolumn annotation.

In my application 2 entity classes are there User and ProductDetail and i am trying to do One-to-many association between them.I am expecting user-id as foreign key in ProductDetail table.

There is no error while running my program and when i am passing the JSON statement as input to testcase my application in postman,but when i am seeing my MySql database to see if mapping occured or not, user id is not mapped as a foreign key in ProductDetail table.

I am posting the Entity classes and other classes below.....

Please help i am really stuck please let me know what i am going wrong(I know i am missing very small thing which i am unable to figure out on my own)

User class:-

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
@Entity
public class User {

    @Id
    @GeneratedValue
    int id;
    String name;
    String gender;
    String emailId;

    @OneToMany(targetEntity = ProductDetail.class,cascade = CascadeType.ALL)
    @JoinColumn(name="up_fk",referencedColumnName = "id")
    private List userpurchase;

}

ProductDetail class:-

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
@Entity
public class ProductDetail
{
    @Id
    private int productid;
    private String productname;
    private  int cost;
}

Controller class:-

@RestController
@RequestMapping("/Ecommerce")
public class UserController
{
    @Autowired
    private ProductService productservice;
    @Autowired
    private ProductRepository productRepository;
    @Autowired
    private UserRepository userRepository;

    @GetMapping("/products")
    public List ShowProducts()
    {
        return productservice.getProducts();
    }

    @PostMapping("/PlaceOrder")
    public User placeOrder(@RequestBody OrderRequest request)
    {
        return userRepository.save(request.getUser());
    }
}

OrderRequest:- class which only contains User object from which we extract user object and it will contain list of products..

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class OrderRequest
{
    private User user;
}

application.properties file:-

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/ecommerceapi
spring.datasource.username=root
spring.datasource.password=deep
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto =update
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

user_4506703 · Answer

Correct name is userpurchase, not ProductDetail.

{
  "user": {
    "name": "deep",
    "gender": "male",
    "emailId": "d@gmail.com",
    "userpurchase": [
      {
        "productid": 2,
        "productname": "laptop",
        "cost": 50000
      },
      {
        "productid": 3,
        "productname": "earphone",
        "cost": 500
      }
    ]
  }
}

user_10162200 · Answer

I think the structure is wrong, how do you know which order asosiated with which products. If the user cancelled an order which product should not be sent? Your order should contain a list of products and one user.

One to many assosiation using @Onetomany @JoinColumn in spring boot?

2 Answers