Querying an EF Core model

Open the Program.cs file and import the following namespaces:

using static System.Console; 
using Packt.CS7; 
using Microsoft.EntityFrameworkCore; 
using System.Linq;

In Program, define a QueryingCategories method, and add the following statements to do these:

• Create an instance of the Northwind class that will manage the database
• Create a query for all categories that includes their related products
• Enumerate through the categories, outputting the name and number of products for each one:

static void QueryingCategories()
{ 
   using (var db = new Northwind()) 
   { 
      WriteLine("Categories and how many products they have:"); 
 
      // a query to get all categories and their related products
      IQueryable<Category> cats = db.Categories.Include(c => c.Products); 
 
      foreach (Category c in cats) 
      { 
         WriteLine...