public int AssaignCourseTeacher(Teacher teacher) { int assaigned = 0; if (anTeacherGateway.IsCourseAssaigned(teacher)) { assaigned = 2; } else { int isRowAffected = anTeacherGateway.AssaignCourseTeacher(teacher); if (isRowAffected > 0) { double remain = teacher.CreditLeft - teacher.Credit; anTeacherGateway.UpdateTeacherCredit(remain, teacher.Id); assaigned = 1; } else { assaigned = 2; } } return(assaigned); }