private void createTeacher(Teacher t)
{
using (var dbCtx = new SchoolDBEntities())
{
//Add Student object into Students DBset
dbCtx.Teachers.Add(t);
// call SaveChanges method to save student into database
dbCtx.SaveChanges();
}
}
private void createStandard(Standard std)
{
using (var dbCtx = new SchoolDBEntities())
{
//Add Student object into Students DBset
dbCtx.Standards.Add(std);
// call SaveChanges method to save student into database
dbCtx.SaveChanges();
}
}
private bool createStudent(Student s)
{
using (var dbCtx = new SchoolDBEntities())
{
//Add Student object into Students DBset
dbCtx.Students.Add(s);
// call SaveChanges method to save student into database
dbCtx.SaveChanges();
}
return true;
}
private bool deleteStudentAddress(string sName)
{
Student studentToDelete;
//1. Get student from DB
using (var ctx = new SchoolDBEntities())
{
studentToDelete = ctx.Students.Where(s => s.StudentName == sName).FirstOrDefault<Student>();
ctx.Entry(studentToDelete.StudentAddress).State = System.Data.Entity.EntityState.Deleted;
ctx.SaveChanges();
}
return true;
}
private void Form1_Load(object sender, EventArgs e)
{
// 1. Add 2 students
Student s1 = new Student();
s1.StudentName = "aaa aaa";
s1.StudentAddress = new StudentAddress();
s1.StudentAddress.Address1 = "123 aaa";
s1.StudentAddress.Address2 = "345 aaa";
s1.StudentAddress.City = "Long Beach";
s1.StudentAddress.State = "California";
Student s2 = new Student();
s2.StudentName = "bbb bbb";
s2.StudentAddress = new StudentAddress();
s2.StudentAddress.Address1 = "123 bbb";
s2.StudentAddress.Address2 = "345 bbb";
s2.StudentAddress.City = "Long Beach";
s2.StudentAddress.State = "California";
createStudent(s1);
createStudent(s2);
// 2. Display 2 students
textBox1.Text += readStudent("*");
// 3. update student a: adress
updateStudent("aaa aaa");
// 4. display student a
printDivider();
textBox1.Text += readStudent("aaa aaa");
// 5. delete student a: adress
deleteStudentAddress("aaa aaa");
// 6. display student a
printDivider();
textBox1.Text += readStudent("aaa aaa");
// 7. create 2 standard objects
Standard std1 = new Standard();
std1.StandardName = "FT";
std1.Description = "Full-Time Instructor";
Standard std2 = new Standard();
std2.StandardName = "PT";
std2.Description = "Part-Time Instructor";
createStandard(std1);
createStandard(std2);
// 8. Create 3 teacher objects
Teacher t1 = new Teacher();
t1.TeacherName = "Teacher Name 1";
Teacher t2 = new Teacher();
t2.TeacherName = "Teacher Name 2";
Teacher t3 = new Teacher();
t3.TeacherName = "Teacher Name 3";
createTeacher(t1);
createTeacher(t2);
createTeacher(t3);
// 9. Add t1, t2 to std1, and t3 to std2
updateStandard(t1, t2, std1);
updateStandard2(t3, std2);
// 10. Display t1, t2, t3, and their standard name and description
printDivider();
string output = "";
using (var ctx = new SchoolDBEntities())
{
var teachers = (from teach in ctx.Teachers
select teach);
foreach (Teacher t in teachers)
output += "\r\nStandard Name: " + t.Standard.StandardName +
"\r\nStandard Description: " + t.Standard.Description +
"\r\nTeacher Name: " + t.TeacherName;
}
textBox1.Text += output;
printDivider();
// 11. Update std1 description
using (var ctx = new SchoolDBEntities())
{
//fetching existing standard from the db
Standard std = (from s in ctx.Standards.Include("Teachers")
where s.StandardName == "FT"
select s).FirstOrDefault<Standard>();
std.Description = "Full Time Intstructor Updated";
ctx.SaveChanges();
}
// 12. Display all teachers who are full time
using (var ctx = new SchoolDBEntities())
{
var results = (from t in ctx.Teachers
where t.Standard.StandardName == "FT"
select t);
foreach (Teacher t in results)
textBox1.Text += "\r\nTeacher Name: " + t.TeacherName +
"\r\nDescription: " + t.Standard.Description;
}
printDivider();
// 13. change the standard id of t1, to standard id of part time instructor
using (var ctx = new SchoolDBEntities())
{
Teacher teacher1 = ctx.Teachers.Where(s => s.TeacherName == "Teacher Name 1").FirstOrDefault<Teacher>();
Standard standard2 = ctx.Standards.Where(s => s.StandardName == "PT").FirstOrDefault<Standard>();
int newID = standard2.StandardId;
teacher1.StandardId = newID;
ctx.Entry(teacher1).State = EntityState.Modified;
ctx.SaveChanges();
textBox1.Text += "NEW ID: " + teacher1.StandardId + "\r\nNAME: " + teacher1.TeacherName;
}
// 14. display t1, with description
}
private bool updateStudent(string sName)
{
Student stud;
//1. Get student from DB
using (var ctx = new SchoolDBEntities())
{
stud = ctx.Students.Where(s => s.StudentName == sName).FirstOrDefault<Student>();
if (stud != null)
{
stud.StudentAddress.Address1 = "123 aaa new";
}
//3. Mark entity as modified
ctx.Entry(stud).State = System.Data.Entity.EntityState.Modified;
//4. call SaveChanges
ctx.SaveChanges();
}
return true;
}
private void updateStandard2(Teacher t, Standard stnd)
{
Standard std = null;
using (var ctx = new SchoolDBEntities())
{
//fetching existing standard from the db
std = (from s in ctx.Standards.Include("Teachers")
where s.StandardName == stnd.StandardName
select s).FirstOrDefault<Standard>();
Teacher teach1 = ctx.Teachers.Where(s => s.TeacherName == t.TeacherName).FirstOrDefault<Teacher>();
std.Teachers.Add(teach1);
ctx.SaveChanges();
}
}
private string readStudent(string s)
{
string returnValue = "Error Reading...";
if (s.Equals("*")) //get all
{
using (var ctx = new SchoolDBEntities())
{
var student = (from st in ctx.Students
select st);
printDivider();
returnValue = "";
foreach (Student st in student)
{
returnValue += "\r\nName: " + st.StudentName +
"\r\nAddress1: " + st.StudentAddress.Address1 +
"\r\nAddress2: " + st.StudentAddress.Address2;
}
}
}
else //get specific
{
using (var ctx = new SchoolDBEntities())
{
var student = ctx.Students.Where(st => st.StudentName == s).FirstOrDefault<Student>();
printDivider();
returnValue = "";
if (student.StudentAddress != null)
{
returnValue += "\r\nName: " + student.StudentName +
"\r\nAddress1: " + student.StudentAddress.Address1 +
"\r\nAddress2: " + student.StudentAddress.Address2;
}
else
{
returnValue += "\r\nName: " + student.StudentName +
"\r\nAddress1: NULL"+
"\r\nAddress2: NULL";
}
}
}
return returnValue;
}
