private static void DeleteStudentsFromPhysics(ClassDB ctx)
{
var physics = ctx.Classes.First(c => c.Name == "Physics");
physics.Students.Clear();
ctx.SaveChanges();
}
private static void DeleteStudentsFromClasses(ClassDB ctx)
{
var students = ctx.Students.ToList();
foreach (var student in students)
{
ctx.DeleteObject(student);
}
ctx.SaveChanges();
}
private static void DeleteClasses(ClassDB ctx)
{
var classes = ctx.Classes.ToList();
foreach (var @class in classes)
{
ctx.DeleteObject(@class);
}
ctx.SaveChanges();
}
static void Main(string[] args)
{
var ctx = new ClassDB();
AddStudents(ctx);
AddClasses(ctx);
ctx.SaveChanges();
AssociateStudentsWithClasses(ctx);
DeleteClasses(ctx);
DeleteStudentsFromPhysics(ctx);
DeleteStudentsFromClasses(ctx);
}
private static void AssociateStudentsWithClasses(ClassDB ctx)
{
var students = ctx.Students.ToList();
var physics = ctx.Classes.First(c => c.Name == "Physics");
foreach (var student in students)
{
physics.Students.Add(student);
}
var music = ctx.Classes.First(c => c.Name == "Music");
foreach (var student in students.Take(2))
{
music.Students.Add(student);
}
var art = ctx.Classes.First(c => c.Name == "Art");
art.Students.Add(students.First());
ctx.SaveChanges();
}