public static void AddManyToManyEntity()
{
//Create student entity
var student1 = new Student();
student1.StudentName = "New Student2";
//Standard std = new Standard() { StandardName = "New Standard2" };
//student1.Standard = std;
//var student2 = new Student();
//student2.StudentName = "New Student3";
//student2.Standard = std;
//Create course entities
var course1 = new Course();
course1.CourseName = "New Course1";
course1.Location = "City1";
var course2 = new Course();
course2.CourseName = "New Course2";
course2.Location = "City2";
var course3 = new Course();
course3.CourseName = "New Course3";
course3.Location = "City1";
//var teacher1 = new Teacher();
//teacher1.TeacherName = "New teacher4";
////assign teacher1 for each courses
//course1.Teacher = teacher1;
//course2.Teacher = teacher1;
//course3.Teacher = teacher1;
// add multiple courses for student entity
student1.Courses.Add(course1);
student1.Courses.Add(course2);
student1.Courses.Add(course3);
//student2.Courses.Add(course2);
using (var dbCtx = new SchoolDBEntities())
{
//add student into DBContext
dbCtx.Students.Add(student1);
//dbCtx.Students.Add(student2);
//Alternate method of adding entity into DBContext
//dbCtx.Entry(student1).State = System.Data.EntityState.Added;
//call SaveChanges
dbCtx.SaveChanges();
}
Console.WriteLine("AddManyToManyEntity successfull");
}
public static void AddOneToOneEntity()
{
// create new student entity object
var student = new Student();
// Assign student name
student.StudentName = "New Student1";
// Create new StudentAddress entity and assign it to student entity
student.StudentAddress = new StudentAddress()
{
Address1 = "Student1's Address1", Address2 = "Student1's Address2", City = "Student1's City", State = "Student1's State"
};
//create DBContext object
using (var dbCtx = new SchoolDBEntities())
{
//Add student object into Student's EntitySet
dbCtx.Students.Add(student);
//Alternate method of adding one-to-one entity graph
//dbCtx.Entry(student).State = System.Data.EntityState.Added;
// call SaveChanges method to save student & StudentAddress into database
dbCtx.SaveChanges();
}
Console.WriteLine("AddOneToOneEntity successfull");
}
public static void AddOneToManyEntity()
{
//Create new standard
var standard = new Standard();
standard.StandardName = "Standard1";
//create new teachers
var teacher1 = new Teacher();
teacher1.TeacherName = "New Teacher1";
var teacher2 = new Teacher();
teacher2.TeacherName = "New Teacher2";
var teacher3 = new Teacher();
teacher3.TeacherName = "New Teacher3";
//add teachers for new standard
standard.Teachers.Add(teacher1);
standard.Teachers.Add(teacher2);
standard.Teachers.Add(teacher3);
using (var dbCtx = new SchoolDBEntities())
{
//add standard entity into standards entitySet
dbCtx.Standards.Add(standard);
//Save whole entity graph to the database
dbCtx.SaveChanges();
}
Console.WriteLine("AddOneToManyEntity successfull");
}
public static void ValidationErrorDemo()
{
try
{
using (var ctx = new SchoolDBEntities())
{
ctx.Students.Add(new Student()
{
StudentName = ""
});
ctx.Standards.Add(new Standard()
{
StandardName = ""
});
Console.WriteLine("***ValidationErrorDemo Start");
ctx.SaveChanges();
}
}
catch (DbEntityValidationException dbEx)
{
foreach (DbEntityValidationResult entityErr in dbEx.EntityValidationErrors)
{
foreach (DbValidationError error in entityErr.ValidationErrors)
{
Console.WriteLine("Error Property Name {0} : Error Message: {1}",
error.PropertyName, error.ErrorMessage);
}
}
Console.WriteLine("***ValidationErrorDemo End");
}
}
public static void DeleteEntity()
{
Teacher tchr;
// Get student from DB
using (var ctx = new SchoolDBEntities())
{
tchr = ctx.Teachers.Where(t => t.TeacherName == "Teacher 1").FirstOrDefault <Teacher>();
}
//Delete entity using new context
using (var dbCtx = new SchoolDBEntities())
{
if (tchr != null)
{
//if already loaded in existing DBContext then use Set().Remove(entity) to delete it.
var newtchr = dbCtx.Teachers.Where(t => t.TeacherId == tchr.TeacherId).FirstOrDefault <Teacher>();
dbCtx.Set <Teacher>().Remove(newtchr);
//dbCtx.Teachers.Remove(newtchr);
//Mark entity as deleted
//dbCtx.Entry(tchr).State = System.Data.EntityState.Deleted;
dbCtx.SaveChanges();
}
}
Console.WriteLine("DeleteEntity Successfull");
}
public static void UpdateManyToManyEntity()
{
Student stud;
IList <Course> courseList = null;
// Get student from DB
using (var ctx = new SchoolDBEntities())
{
stud = ctx.Students.Include("Courses").Where(s => s.StudentID == 1).FirstOrDefault <Student>();
courseList = ctx.Courses.ToList <Course>();
}
if (stud.Courses != null)
{
Course cours = stud.Courses.FirstOrDefault <Course>();
//removing first course from student's existing courses
stud.Courses.Remove(cours);
}
//Add existing courses to student's course list
if (stud.Courses.Count > 0)
{
stud.Courses.Add(courseList[1]);
}
//stud.Courses.Add(courseList[6]);
using (var dbCtx = new SchoolDBEntities())
{
//Get existing data from database
var existingStudent = dbCtx.Students.Include("Courses").Where(s => s.StudentID == stud.StudentID).FirstOrDefault <Student>();
//Find deleted courses from student's course collection by students' existing courses (existing data from database) minus students' current course list (came from client in disconnected scenario)
var deletedCourses = existingStudent.Courses.Except(stud.Courses, cours => cours.CourseId).ToList <Course>();
//Find Added courses in student's course collection by students' current course list (came from client in disconnected scenario) minus students' existing courses (existing data from database) -
var addedCourses = stud.Courses.Except(existingStudent.Courses, cours => cours.CourseId).ToList <Course>();
//Remove deleted courses from students' existing course collection (existing data from database)
deletedCourses.ForEach(c => existingStudent.Courses.Remove(c));
//Add new courses
foreach (Course c in addedCourses)
{
//Attach courses because it came from client as detached state in disconnected scenario
if (dbCtx.Entry(c).State == System.Data.EntityState.Detached)
{
dbCtx.Courses.Attach(c);
}
//Add course in existing student's course collection
existingStudent.Courses.Add(c);
}
//Save changes which will reflect in StudentCourse table only
dbCtx.SaveChanges();
}
Console.WriteLine("UpdateOneToOneEntity successfull");
}
public static void UpdateEntity()
{
Student stud;
// Get student from DB
using (var ctx = new SchoolDBEntities())
{
stud = ctx.Students.Where(s => s.StudentID == 1).FirstOrDefault <Student>();
}
// change student name in disconnected mode (out of DBContext scope)
if (stud != null)
{
stud.StudentName = "Updated Student1";
}
//save modified entity using new DBContext
using (var dbCtx = new SchoolDBEntities())
{
//Mark entity as modified
if (stud != null)
{
dbCtx.Entry(stud).State = System.Data.EntityState.Modified;
dbCtx.SaveChanges();
}
}
Console.WriteLine("UpdateEntity successfull");
}
public static void AddEntity()
{
// create new Standard entity object
var newStandard = new Standard();
// Assign standard name
newStandard.StandardName = "Standard 1";
//create DBContext object
using (var dbCtx = new SchoolDBEntities())
{
//Add standard object into Standard DBset
dbCtx.Standards.Add(newStandard);
// call SaveChanges method to save standard into database
dbCtx.SaveChanges();
}
Console.WriteLine("AddEntity successfull");
}
public static void UpdateOneToOneEntity()
{
Student stud;
// Get student from DB
using (var ctx = new SchoolDBEntities())
{
stud = ctx.Students.Include(s => s.StudentAddress).Where(s => s.StudentID == 1).FirstOrDefault <Student>();
}
// change student name in disconnected mode (out of context scope)
if (stud != null)
{
stud.StudentName = "updated student";
if (stud.StudentAddress == null)
{
stud.StudentAddress = new StudentAddress();
stud.StudentAddress.StudentID = stud.StudentID;
stud.StudentAddress.Address1 = "address444";
stud.StudentAddress.Address2 = "add222";
stud.StudentAddress.City = "city444";
stud.StudentAddress.State = "State444";
}
else if (stud.StudentAddress != null) // delete address
{
stud.StudentAddress = null;
}
}
//save modified entity using new context
using (var dbCtx = new SchoolDBEntities())
{
StudentAddress existingStudentAddress = dbCtx.StudentAddresses.Where(addr => addr.StudentID == stud.StudentID).FirstOrDefault <StudentAddress>();
//Mark each entity as modified
dbCtx.Entry(stud).State = System.Data.EntityState.Modified;
//dbCtx.Entry(stud.StudentAddress).State = System.Data.EntityState.Modified;
if (existingStudentAddress != null)
{
dbCtx.Entry <StudentAddress>(existingStudentAddress).State = System.Data.EntityState.Deleted;
if (stud.StudentAddress != null)
{
dbCtx.StudentAddresses.Add(stud.StudentAddress);
}
}
else
{
dbCtx.StudentAddresses.Add(stud.StudentAddress);
}
if (dbCtx.GetValidationErrors().Count() <= 0)
{
dbCtx.SaveChanges();
}
}
Console.WriteLine("UpdateOneToOneEntity successfull");
}
public static void UpdateOneToManyEntity()
{
Student stud;
// Get student from DB
using (var ctx = new SchoolDBEntities())
{
ctx.Configuration.ProxyCreationEnabled = false;
stud = ctx.Students.Where(s => s.StudentID == 1).Include(s => s.Standard.Teachers).FirstOrDefault <Student>();
}
var teachers = stud.Standard.Teachers.ToList <Teacher>();
foreach (Teacher tchr in teachers)
{
tchr.TeacherName = "Updated " + tchr.TeacherName;
}
//add new teacher
teachers.Add(new Teacher()
{
TeacherName = "New teacher4"
});
teachers.Add(new Teacher()
{
TeacherName = "New teacher5"
});
teachers.RemoveAt(1);
using (var dbCtx = new SchoolDBEntities())
{
//Get fresh data from database
var existingStudent = dbCtx.Students.AsNoTracking().Include(s => s.Standard).Include(s => s.Standard.Teachers).Where(s => s.StudentID == stud.StudentID).FirstOrDefault <Student>();
var existingTeachers = existingStudent.Standard.Teachers.ToList <Teacher>();
var updatedTeachers = teachers.ToList <Teacher>();
//Find newly added teachers by updatedTeachers - existingTeacher = newly added teacher
var addedTeachers = updatedTeachers.Except(existingTeachers, tchr => tchr.TeacherId);
//Find deleted teachers by existing teachers - updatedTeachers = deleted teachers
var deletedTeachers = existingTeachers.Except(updatedTeachers, tchr => tchr.TeacherId);
//Find modified teachers by updatedTeachers - addedTeachers = modified teachers
var modifiedTeacher = updatedTeachers.Except(addedTeachers, tchr => tchr.TeacherId);
//Mark all added teachers entity state to Added
addedTeachers.ToList <Teacher>().ForEach(tchr => dbCtx.Entry(tchr).State = System.Data.EntityState.Added);
//Mark all deleted teacher entity state to Deleted
deletedTeachers.ToList <Teacher>().ForEach(tchr => dbCtx.Entry(tchr).State = System.Data.EntityState.Deleted);
//Apply modified teachers current property values to existing property values
foreach (Teacher teacher in modifiedTeacher)
{
//Find existing teacher by id from fresh database teachers
var existingTeacher = dbCtx.Teachers.Find(teacher.TeacherId);
if (existingTeacher != null)
{
//Get DBEntityEntry object for each existing teacher entity
var teacherEntry = dbCtx.Entry(existingTeacher);
//overwrite all property current values from modified teachers' entity values,
//so that it will have all modified values and mark entity as modified
teacherEntry.CurrentValues.SetValues(teacher);
}
}
//Save all above changed entities to the database
dbCtx.SaveChanges();
}
Console.WriteLine("UpdateOneToOneEntity successfull");
}
