public IEnumerable<MarkModel> GetStudentMarks(int studentId)
        {
            var context = new SchoolContext();
            var student = context.Set<Student>().Where(st => st.Id == studentId).FirstOrDefault();

            IEnumerable<MarkModel> marks = student.Marks
                .Select(m => new MarkModel()
                {
                        Id = m.Id,
                        Subject = m.Subject,
                        Score = m.Score
                }).ToList(); ;
            return marks;
        }
 public IQueryable<StudentModel> GetAll()
 {
     AddStudentsToDB();
     var context = new  SchoolContext();
     IQueryable<StudentModel> students = context.Set<Student>()
         .Select(x => new StudentModel()
         {
             Id = x.Id,
             Fname = x.Fname,
             Lname = x.Lname,
             Grade = x.Grade,
             Age = x.Age
         }); ;
     return students;
 }
 // GET api/values
 public IEnumerable<StudentModel> GetAll()
 {
     AddStudentsToDB();
     var context = new  SchoolContext();
     IEnumerable<StudentModel> students = context.Set<Student>().ToList()
         .Select(x => new StudentModel()
         {
             Id = x.Id,
             Fname = x.Fname,
             Lname = x.Lname,
             Grade = x.Grade,
             Age = x.Age,
             Marks = x.Marks.Select(m => new MarkModel
             {
                 Id = m.Id,
                 Subject = m.Subject,
                 Score = m.Score
             }).ToList()
         }).ToList(); ;
     return students;
 }
        private void AddStudentsToDB()
        {
            var context = new  SchoolContext();
            if (context.Set<Student>().ToList().Count == 0)
            {
                context.Students.Add(
                new Student
                {
                    Fname = "Doncho",
                    Lname = "Minkov",
                    Grade = 3,
                    Age = 25,
                    Marks = new List<Mark>()
                    {
                        new Mark { Subject = "Math", Score = 4 },
                        new Mark { Subject = "JavaScript", Score = 6 }
                    }
                });

                context.Students.Add(
                new Student
                {
                    Fname = "Nikolay",
                    Lname = "Kostov",
                    Grade = 2,
                    Age = 222,
                    Marks = new List<Mark>()
                    {
                        new Mark { Subject = "MVC", Score = 6},
                        new Mark { Subject = "JavaScript", Score = 5}
                    }
                });

                context.Students.Add(
                new Student
                {
                    Fname = "Ivaylo",
                    Lname = "Kendov",
                    Grade = 1,
                    Age = 225,
                    Marks = new List<Mark>()
                    {
                        new Mark { Subject = "OOP", Score = 4 },
                        new Mark { Subject = "C#", Score = 6 }
                    }
                });
                context.Students.Add(
                new Student
                {
                    Fname = "Georgi",
                    Lname = "Georgiev",
                    Grade = 1,
                    Age = 219
                });

                context.Students.Add(
                new Student
                {
                    Fname = "Asya",
                    Lname = "Georgieva",
                    Grade = 2,
                    Age = 228,
                    Marks = new List<Mark>()
                    {
                        new Mark { Subject = "Automation Testing", Score = 6 },
                        new Mark { Subject = "Manual Testing", Score = 4 }
                    }
                });

                context.SaveChanges();
            }
        }