Why is my data getting associated with wrong column in mysql db? - mysql

Question

I have two tables connected with a many to many relationship using a composite key:
Table1
#Entity
#Table(name = "user")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(name = "user_name")
private String userName;
#Column(name = "first_name")
private String firstName;
#Column(name = "last_name")
private String lastName;
private String password;
private String authorization;
#OneToMany(
mappedBy = "user",
cascade = CascadeType.ALL,
orphanRemoval = true
)
#JsonManagedReference
private List<UserProduct> userProducts = new ArrayList<>();
#OneToMany(
mappedBy = "user",
cascade = CascadeType.ALL,
orphanRemoval = true
)
private List<Orders> orders = new ArrayList<>();
Table2
#Entity
#Table(name = "product")
public class Product {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String name;
private int price;
private double mass;
private double alcohol;
private String picture;
private int amount;
#OneToMany(
mappedBy = "user",
cascade = CascadeType.ALL,
orphanRemoval = true
)
private List<UserProduct> userProducts = new ArrayList<>();
#OneToMany(
mappedBy = "orders",
cascade = CascadeType.ALL,
orphanRemoval = true
)
private List<OrderProduct> orderProducts = new ArrayList<>();
Table with composite key
#Entity
#Table(name = "user_product")
public class UserProduct {
#EmbeddedId
private UserProductId id;
#ManyToOne(fetch = FetchType.LAZY)
#MapsId("userId")
#JsonBackReference
private User user;
#ManyToOne(fetch = FetchType.LAZY)
#MapsId("productId")
private Product product;
#Column(name = "amount_of_new_products")
private int amountOfNewProducts;
When I make a REST call to UserProduct table so i can update the product value using this payload:
{
"user": 4,
"product": 2,
"amountOfNewProducts": 32
}
it writes the information depending on what is the user id and not the product id. For this payload it would write in like this:
{
"id": 3,
"name": "Grimbergen Blanche",
"price": 132,
"mass": 0.33,
"alcohol": 6.0,
"picture": "https://i.imgur.com/qIq1OrC.png",
"amount": 502,
"userProducts": [],
"orderProducts": []
},
{
"id": 4,
"name": "Grimbergen Blonde",
"price": 132,
"mass": 0.33,
"alcohol": 6.7,
"picture": "https://i.imgur.com/OnioHd5.png",
"amount": 435,
"userProducts": [
{
"id": {
"productId": 2,
"userId": 4
},
"product": {
"id": 2,
"name": "Lav Premium",
"price": 73,
"mass": 0.33,
"alcohol": 4.9,
"picture": "https://i.imgur.com/T3gCAOE.png",
"amount": 1862,
"userProducts": [],
"orderProducts": []
},
"amountOfNewProducts": 32
}
],
"orderProducts": []
},
So basically even though i passed in 2 as product id the information will be written in product with id 4 just because the users id is 4. Any kind of a clue where I might me messing up would be appreciated.

Answer 1

You need to fix mappedBy = "user" in Product entity. It must be "product", like this:
#OneToMany(
mappedBy = "product",
cascade = CascadeType.ALL,
orphanRemoval = true
)
private List<UserProduct> userProducts = new ArrayList<>();
Also check that you have correct #JoinColumn in UserProductId (ufortunately, you didn't put code for it to the question).