How to save an object that contains a list of integers in a postgres database - spring

Question

i have an object called Cart i want to save it in the database with an array/list of integers that rappresents Product's id.
This is my Cart class at the moment:
public class Cart {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", nullable = false)
private Integer id;
#Column(name = "customer_fk")
private Integer customerFk;
#Column(name = "product_list")
private List<Integer> productList;
}
i saw that postgres has the integer[] datatype
I'm using spring.jpa.hibernate.ddl-auto=create to create the database
How do i tell to spring and jpa to save that list as an integer in the DB?
(if i can)
Is this a good solution?
I actually found a solution that works, using Strings, but im too curious to see if find a way to do it with arrays

Answer 1

The canonical approach here would be to maintain a table of products and then map carts to products in a one to many relationship. You could try:
#Entity
#Table(name = "Cart")
public class Cart {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", nullable = false)
private Integer id;
#Column(name = "customer_fk")
private Integer customerFk;
#Column(name = "product_list")
#OneToMany(mappedBy="cart", cascade = CascadeType.ALL)
private List<Product> productList;
}
#Entity
#Table(name = "Product")
public class Product {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", nullable = false)
private Integer id;
#ManyToOne
#JoinColumn(name = "FK_Cart")
private Cart cart;
// more fields, getters and setters
}
This is not a complete implementation, but the idea is that each product ID should exist in a dedicated products table, and each cart entity should track its product references via a foreign key relationship.