如何使用自动生成的值制作复合主键，并使用休眠和Spring MVC制作一个外键

Question

I am developing a web application that customer call to a employee and he put a customer's order to the system.

From my ER diagram , the OrderDetail class contain a composite primary key that orderId and productId . Also it contain orderedQuentity column. What I want is when customer place a order it has to have what products he/she ordered and the quantity of each product he/she order and who place the order(the employee).....

But I feel that in my way of doing that, the orderDetail class can only contain list of product , not the quantity of each product.

How do I do what I want ??

Here is my entity classes that I try to implement.

Customer Class :

@Entity
public class Customer {

    @Id
    @GeneratedValue
    private Integer id;
    private String firstName;
    private String lastName;
    private String companyName;
    private Integer teleponeNumber;

    @OneToMany(mappedBy="customer")
    private List<OrderDetail> orders;

}

Product Class :

@Entity

public class Product {

    @Id
    @GeneratedValue
    private Integer id;
    private String name;
    private Integer availableQuantity;
    private String unitType;
    private Integer unitPrice;
    private String description;

    @ManyToMany(mappedBy="products")
    private List<OrderDetail> details;

}

Order Class :

@Entity

public class OrderDetail {

    @Id
    @GeneratedValue
    private Integer orderId;
    private Integer orderedQuentity;    
    private String customerAddress;
    private String shipingAddress;
    private String orderStatus;

    @ManyToOne
    @JoinColumn(name="Employee_Id")
    private Employee employee;

    @ManyToOne
    @JoinColumn(name="customer_id")
    private Customer customer;

    @ManyToMany
    @JoinTable
    private List<Product> products;
}

Employee Class :

@Entity
public class Employee {

    @Id
    @GeneratedValue
    private Integer id;
    private String firstName;
    private String lastName;
    private String designation;
    private String email;
    private String password;

    @OneToMany(mappedBy="employee")
    private List<OrderDetail> orders;
}

Answer 1

From Customer to OrderDetail you have a OneToMany relation, I would suggest you to create a JoinTable

So the customer entity will look like:

@Entity
public class Customer {

@Id
@GeneratedValue
private Integer id;
private String firstName;
private String lastName;
private String companyName;
private Integer teleponeNumber;

@OneToMany(mappedBy="customer")
@JoinTable(name = “customer_order_details”, joinColumns= { @JoinColumn(name = “customer_id”, referencedColumnName=”id”) }, inverseJoinColumns = { @JoinColumn(name = “order_id”, referencedColumnName = “id”) })
private List<OrderDetail> orders;

}

The same situation in Employee entity:

@Entity
public class Employee {

@Id
@GeneratedValue
private Integer id;
private String firstName;
private String lastName;
private String designation;
private String email;
private String password;

@OneToMany(mappedBy="employee")
@JoinTable(name = “employee_order_details”, joinColumns= {     @JoinColumn(name = “employee_id”, referencedColumnName=”id”) }, inverseJoinColumns = { @JoinColumn(name = “order_id”, referencedColumnName = “id”) })

private List<OrderDetail> orders;

}

And Product entity:

@Entity

public class Product {

@Id
@GeneratedValue
private Integer id;
private String name;
private Integer availableQuantity;
private String unitType;
private Integer unitPrice;
private String description;

@ManyToMany(mappedBy="products")
@JoinTable(name = “product_order_details”, joinColumns= { @JoinColumn(name = “product_id”, referencedColumnName=”id”) }, inverseJoinColumns = { @JoinColumn(name = “order_id”, referencedColumnName = “id") })
private List<OrderDetail> details;