/// <summary>
/// LINQ method to insert a new lecturer object
/// </summary>
/// <returns>A bool to confirm/deny insert</returns>
public bool InsertLecturer(Lecturer l)
{
try
{
using (LinqDBDataContext db = new LinqDBDataContext())
{
db.Lecturers.InsertOnSubmit(l);
db.SubmitChanges();
}
}
catch (SqlException sqlException)
{
this.ErrorMessage = "SQL Error: " + sqlException.Message;
return(false);
}
catch (InvalidOperationException invalidOperationException)
{
this.ErrorMessage = "SQL Operation Error: " + invalidOperationException.Message;
return(false);
}
catch (Exception e)
{
this.ErrorMessage = "Error: " + e.Message;
return(false);
}
return(true);
}
/// <summary>
/// LINQ method to insert a new subject object
/// </summary>
/// <returns>int count to confirm/deny insert</returns>
public int InsertNewSubject(Subject s)
{
int count;
try
{
using (LinqDBDataContext db = new LinqDBDataContext())
{
count = db.Subjects.Count(n => n.SubjectName.Equals(s.SubjectName));
if (count == 0)
{
db.Subjects.InsertOnSubmit(s);
db.SubmitChanges();
}
}
}
catch (SqlException sqlException)
{
this.ErrorMessage = "SQL Error: " + sqlException.Message;
return(-1);
}
catch (InvalidOperationException invalidOperationException)
{
this.ErrorMessage = "SQL Operation Error: " + invalidOperationException.Message;
return(-1);
}
catch (Exception e)
{
this.ErrorMessage = "Error: " + e.Message;
return(-1);
}
return(count);
}
/// <summary>
/// LINQ method to either add a new subject and grade to a student or update the grade of
/// and existing subject
/// </summary>
/// <returns>A count in int form</returns>
public int UpdateSubjectDetails(Grade g)
{
int count;
try
{
using (LinqDBDataContext db = new LinqDBDataContext())
{
count = db.Grades.Count(n => n.SubjectID.Equals(g.SubjectID) && n.StudentID.Equals(g.StudentID));
if (count == 0)
{
db.Grades.InsertOnSubmit(g);
db.SubmitChanges();
}
else
{
Grade grade = db.Grades.FirstOrDefault(e => e.SubjectID.Equals(g.SubjectID) && e.StudentID.Equals(g.StudentID));
grade.Grade1 = g.Grade1;
db.SubmitChanges();
}
}
}
catch (SqlException sqlException)
{
this.ErrorMessage = "SQL Error: " + sqlException.Message;
return(-1);
}
catch (InvalidOperationException invalidOperationException)
{
this.ErrorMessage = "SQL Operation Error: " + invalidOperationException.Message;
return(-1);
}
catch (Exception e)
{
this.ErrorMessage = "Error: " + e.Message;
return(-1);
}
return(count);
}
/// <summary>
/// LINQ method to insert a list of subjects for the new student above
/// </summary>
/// <returns>A bool to confirm/deny insert</returns>
public bool InsertGrades(List <Grade> gList)
{
try
{
foreach (var item in gList)
{
using (LinqDBDataContext db = new LinqDBDataContext())
{
Grade g = new Grade();
g.StudentID = item.StudentID;
g.SubjectID = item.SubjectID;
g.DateEntered = DateTime.Now;
db.Grades.InsertOnSubmit(g);
db.SubmitChanges();
}
}
}
catch (SqlException sqlException)
{
this.ErrorMessage = "SQL Error: " + sqlException.Message;
return(false);
}
catch (InvalidOperationException invalidOperationException)
{
this.ErrorMessage = "SQL Operation Error: " + invalidOperationException.Message;
return(false);
}
catch (Exception e)
{
this.ErrorMessage = "Error: " + e.Message;
return(false);
}
return(true);
}
