public static void Main(string[] args)
{
//QueryOne();
//QueryTwo();
//QueryThree();
//QueryFour();
//QueryFive();
//QuerySix();
// Avoid nesting LINQ queries in loops at all cost!
// This almost always leads to performance bottlenecks
// Single() vs First()
// Always have in mind the "N+1" problem, when accessing navigation properties
// i.e. Person.Address.Country.Town.Street
}