如何防止一对多关系中的重复？

Question

I have 2 tables named Company and Customer . One-to-Many relationship , where a company can have many customers and a customer belongs to this company.

Company Table                    Customers Table  
Company Id,                       Customer_ID,    
Company Name,                     Customer_Name,
Company Address                   Phone_no.

In the seeder,

factory(App\Company::class, 5)->create()->each(function ($data) {
            $customers= factory(App\Customer::class, 5)->make();
            $data->customers()->saveMany($customers);

          });

so, each company generates 5 customers each.

The Idea is

company_id         customerId
 1,1,1,1,1         1,2,3,4,5 // the customerId should not be repeated again like 1,2,2,3,4,
 2,2,2,2,2         2,3,6,7,8 // should not be 2,3,3,3,6
 3,3,3,3,3         5,7,8,9,2 and so on 

A company can have many customers but not the customer's with the sameId. How to avoid the duplication for the customerID using php?, and a condition to check if the company has already the customer with the SameId, then remove them from the customer? Could anyone please help? Thanks.

Answer 1

Try this instead

factory(Company::class, 5)->create()->each(function ($company){
        $company->customers()
            ->createMany(factory(Customer::class, 5)->make()->map->getAttributes());
    });