public int CheckIfLectureAlreadyExists(Models.BU.Lecture lecture)
{
Models.Database db = new Models.Database();
string query = "SELECT LectureId FROM Lecture WHERE TeacherId = '" + lecture.teacher.UserID + "' AND Period = '" + lecture.period + "' AND Week = '" + lecture.week + "'" +
"AND Day = '" + lecture.day + "' AND StartHour = '" + lecture.startHour + "' AND StartMinute = '" + lecture.startMinute + "'" +
"AND EndHour = '" + lecture.endHour + "' AND EndMinute = '" + lecture.endMinute + "'";
return(db.CheckIfLectureAlreadyExists(query));
}