static void Print(UniversityEntities context)
{
foreach (var item in context.Student)
{
Console.WriteLine($"{item.Name} {item.Surname} ==> {item.Groups.Name}");
}
}
//Entity Framework - ORM
//Entity - сутність БД(запис таблиці)
//alt enter enter -свтрорити медод з видыленого коду
static void Main(string[] args)
{
//DB first
//Model first
//Code first !!
Console.OutputEncoding = Encoding.UTF8;
UniversityEntities context = new UniversityEntities();
Print(context);
//Add(context);
//Delete(context);
//Update(context);
Console.WriteLine("===========================");
//Вивести всіх студентів групи А123
//AllStudentFromSomeGroup(context);
//Print(context);
//Console.WriteLine("===========================");
//Знайти кількість студентів у групах Р123 та Р456 разом
//StudentCount(context);
//Знайти студента з максимальною оцінкою по предмету С++
//StudentWithMaxMark(context);
//Вивести всі предмети, які читає Андрій Трофімчук
//AllSubjectsForSomeTeacher(context);
//Знайти, скільки студентів з іменем Оля є в БД
//CountOfStudentForSomeName(context);
//Студенту з мінімальною оцінкою по предмету С# змінити прізвище
ChangeSurname(context);
}
static void Delete(UniversityEntities context)
{
Console.WriteLine("===>> Enter name to delete");
string name = Console.ReadLine();
context.Student.Remove(context.Student.FirstOrDefault(x => x.Name == name));
context.SaveChanges();
}
static void Update(UniversityEntities context)
{
Console.WriteLine("===>> Enter ID group for update :");
string group = Console.ReadLine();
Student st = context.Student.FirstOrDefault(x => x.Name == "Alina");
st.Groups.Name = group;
context.SaveChanges();
}
private static void StudentWithMaxMark(UniversityEntities context)
{
var maxMark = context.Achievement.Where(x => x.Subject.Name == "C#").Max(x => x.Mark);
foreach (var item in context.Achievement.Where(x => x.Subject.Name == "C#" && x.Mark == maxMark))
{
Console.WriteLine($"{item.Student.Name} {item.Student.Surname} {item.Subject.Name} = {item.Mark}");
return;
}
}
private static void CountOfStudentForSomeName(UniversityEntities context)
{
int counter = 0;
foreach (var item in context.Student.Where(x => x.Name == "Olia"))
{
counter++;
}
Console.WriteLine($"{counter} students with name Olia");
}
private static void Add(UniversityEntities context)
{
Student st = new Student {
Name = "Olia", Surname = "Olia", Groups = context.Groups.First()
};
//Student st = new Student { Name = "Olia", Surname = "Olia", Groups = new Groups { Name = "Step" } };
context.Student.Add(st);
context.SaveChanges();
}
private static void AllStudentFromSomeGroup(UniversityEntities context)
{
Console.WriteLine("Enter group : ");
string group = Console.ReadLine();
foreach (var item in context.Student.Where(x => x.Groups.Name == group))
{
Console.WriteLine($"{item.Name} {item.Surname} ==> {item.Groups.Name}");
}
}
private static void StudentCount(UniversityEntities context)
{
int count = 0;
foreach (var item in context.Student.Where(x => x.Groups.Name == "B123" || x.Groups.Name == "B456"))
{
count++;
}
Console.WriteLine(count);
}
private static void AllSubjectsForSomeTeacher(UniversityEntities context)
{
int?idDepart = null;
foreach (var item in context.Teacher.Where(x => x.Name == "Andrii" && x.Surname == "Trofimchuk"))
{
idDepart = context.Teacher.Select(c => c.Id_Department).FirstOrDefault();
}
foreach (var item in context.Subject.Where(x => x.Id_Department == idDepart))
{
Console.WriteLine($"{item.Name}");
}
}
private static void ChangeSurname(UniversityEntities context)
{
var minMark = context.Achievement.Where(x => x.Subject.Name == "C#").Min(x => x.Mark);
int?studID = context.Achievement.Where(x => x.Mark == minMark && x.Subject.Name == "C#").Select(x => x.IdStudent).SingleOrDefault();
foreach (var item in context.Student.Where(x => x.Id == studID))
{
Console.WriteLine($"{item.Name} {item.Surname}");
}
Console.WriteLine("===>> Enter Surname to update :");
string surname = Console.ReadLine();
Student st = context.Student.Where(x => x.Id == studID).FirstOrDefault();
st.Surname = surname;
context.SaveChanges();
Print(context);
}
