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; }