Small method for saving student attendance

var studentRepo = new StudentRepository();
int gradeParaleloId = Convert.ToInt32(cmbGradeParalelo.SelectedValue);
var students = studentRepo.FindAllStudentsFromGradeParalelo(gradeParaleloId);

int year = DateTime.Now.Year;
int month = Convert.ToInt32(cmbMes.SelectedIndex) + 1;
AttendanceRepository attendanceRepo = new AttendanceRepository();

for (int i = 0; i < students.Count; i++)
{
    for (int j = 1; j < dataGridView1.Columns.Count; j++)
    {
        DateTime date = new DateTime(year, month, j);

        var student = students[i];
        var attendance = attendanceRepo.FindAttendance(student.StudentId, date);

        if (attendance == null)
        {
            attendance = new Data.Repositories.Attendance();
            attendanceRepo.Add(attendance);
        }

        attendance.StudentId = student.StudentId;
        attendance.DateOfAttendance = date;
        attendance.Attended = dataGridView1[j, i].Value.ToString();
    }
}

attendanceRepo.SaveChanges();

My main thorn in the side is that for each day in the month, I have to query the database, and see if a record already exists in the DB for that day and student.

The upside is that I'm putting each attendance in the datacontext and only pushing the save at the very end as a transaction of sorts.

So I'm not inserting on every day for every student. Imagine for a class of 40 students. That's an easy \$40 * 30 = 1200\$ queries on the spot.

Is there some way for me to streamline this? I'm more concerned about this line:

var attendance = attendanceRepo.FindAttendance(student.StudentId, date);

First of all, minor beef. I'd reccommend that you change your index names to be more descriptive, particularly the inner one. For instance you could make your repo query

DateTime date = new DateTime(year, month, **day**);

Much more readable. When an index has a name, name it.

If you're having performance issues, try separating out the queries. In psuedocode:

foreach day in month
   get students_with_records from database

   foreach student in the_class
      if student NOT in students_with_records
         add record

This method will put the search through the student records on the client...it should be faster, since you will only have one query per day rather than one query per day per student. You really should profile the app and see if it's an issue, though.

StackExchange Code Review Q#1890, answer score: 4