.NET - Entity Framework Core - Map C# Method to SQL Function Demo

Program.cs

class Program
{
    static async Task Main(string[] args)
    {
        // First Unit-of-Work showing Add operation
        AddStudents();

        // Second Unit-of-Work showing Update and Remove operations
        await QueryStudents();
    }

    static void AddStudents()
    {
        using var context = BuildUniversityContext();

        var studentCollection = new List<Student>()
        {
            new Student { FirstName = "John", LastName = "Doe", Address = "4 Privet Drive" },
            new Student { FirstName = "Jane", LastName = "Doe", Address = "6 Privet Drive" },
            new Student { FirstName = "Harry", LastName = "Potter", Address = "8 Privet Drive" },
            new Student { FirstName = "Ginny", LastName = "Weasly", Address = "10 Privet Drive" },
        };

        context.AddRange(studentCollection);
        context.SaveChanges();
    }

    static async Task QueryStudents()
    {
        using var context = BuildUniversityContext();

        // Query using the method GetStudentsCountWithSameLastName
        // Return only those records which surnames appear more than once
        var studentsQuery = from student in context.Students
            where   context.GetStudentsCountWithSameLastName(student.LastName) > 1
            select student;

        // Get Results from Query
        var studentsCollection = await studentsQuery.ToListAsync();

        // Print Results
        Console.WriteLine("---------------------------------------");
        foreach(var student in studentsCollection)
        {
            Console.WriteLine(student);
        }
        Console.WriteLine("---------------------------------------");
    }

    static UniversityContext BuildUniversityContext()
    {
        var dbContextBuilder = new DbContextOptionsBuilder<UniversityContext>();
        var connectionString = "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=University; Integrated Security=True;";
        dbContextBuilder.UseSqlServer(connectionString);
        return new UniversityContext(dbContextBuilder.Options);
    }
}