C++ use traits like in PHP

Question

I am searching a solution how I can define reusable code in C++ like traits in PHP.

Description of the problem: I have three classes (Class, Customer, Admin) and each class must sometimes perform the same action like inserting a new child, adding a new address or adding a new class (same with update and remove action). I want to avoid too develop these functions in every class again.

Further more I would be very nice if these functions are separated from the class "product_name". I don't want to write all these functions into the class "product_name" or "product", because otherwise the class becomes too confusing for too many functions.

Edit
The name of the class "product_name" is a placeholder for my product. At the moment I don't know the name of my product :). And the parent class "product" is a collection point for all products that I would like to develop in the future. I created this class, because I want to use Single-Sign-On and the same user database... So I must develop these parts only once!

Class Diagram of my wish:

Answer 1

C++ is differ from the PHP in many aspects. This is how you can design your domain driven DAO in C++.

This example uses POCO library for database connectivity. You can use any another library for the same propose.

enum class Role {
   ADMIN,
   CUSTOMER,
   SCHOOL_ACCOUNT
}

class User {
protected:
  constexpr User(Role role) noexcept:
    role_(role)
  {}
public:
  User(const User&) = delete;
  User& operator=(const User&) = delete; 
  Role role() const noexcept {
   return role_;
  }
  virtual const char* id() const = 0;
  virtual ~User() = 0;
private:
  Role role_;
};

User::~User() 
{} 

class MyIDGenerator {
public:
  static std::string generate() {
    static POCO::UUIDGenerator gen;
    return gen.create().toString();
  }
};

class Customer final: public User  { 
public:
    Customer() noexcept:
       User(Role.CUSTOMER),
       id_(  MyIDGenerator::generate() ) 
    {} 
    virtual const char* id() const override
    {
      return id_.data();
    }
    virtual ~Customer() override
    {}
private:
   std::string id_;
}
...
// define your Admin and School
...
class Product {
 public:
 Product():
   id_( MyIDGenerator::generate() )
 {} 
 void insertUser(const User* user, const Poco::Data::Session& session) {
  // execute your SQL hire i.e. something like
  POCO::Data::Statement insert(session);
  insert << "insert into product_allowed_user values(?,?)" << use(id_) << use(user->id());
  insert.execute(); 
 }
 private:
   std::string id_;
}