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
Northwindclass 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($"{c.CategoryName} has {c.Products.Count} products.");
}
}
}