static void Main(string[] args)
{
try
{
/////////////////////////////////////////////////////////////////
// Construct the object context
//
// Create Entity ObectContext for School database
SchoolEntities entities = new SchoolEntities();
/////////////////////////////////////////////////////////////////
// Perform the Insert operation
//
Console.Write("Insert data into database...");
// Create a Student object which inherits the Person object
Student newStudent = new Student()
{
FirstName = "Lingzhi",
LastName = "Sun",
EnrollmentDate = DateTime.Now,
Picture = ReadImage(@"MSDN.jpg")
};
// Add the Student object into the Person list
entities.AddToPerson(newStudent);
// Create a Instructor object which inherits the Person object
Instructor newInstructor = new Instructor()
{
FirstName = "Jialiang",
LastName = "Ge",
HireDate = DateTime.Now,
Picture = ReadImage(@"MSDN.jpg")
};
// Create a Course object
Course newCourse1 = new Course()
{
CourseID = 5011,
Title = "Computer",
Credits = 4,
DepartmentID = 1
};
// Create a Course object
Course newCourse2 = new Course()
{
CourseID = 5023,
Title = "Database",
Credits = 3,
DepartmentID = 1
};
// Add the new Course objects into the Instructor object's
// Course list (Many-to-Many Relationship)
newInstructor.Course.Add(newCourse1);
newInstructor.Course.Add(newCourse2);
// Add the Instructor object into the Person list
// This command will also add the corresponding related Course
// objects into the Course list
// We don't need to call entities.AddToCourse method here
entities.AddToPerson(newInstructor);
// Update the changes to the database
int result = entities.SaveChanges();
if (result > 0)
{
Console.WriteLine("SUCCESS\n");
}
/////////////////////////////////////////////////////////////////
// Perform the query operation in one data table
//
Console.WriteLine("\nQuery students whose first name is "
+ "Roger:\n");
// Perform the query
var query = from p in entities.Person
where p.FirstName == "Roger"
select p;
// Display the query results
foreach (var p in query)
{
Console.WriteLine("ID = {0}, Name = {1} {2}", p.PersonID,
p.FirstName, p.LastName);
}
Console.WriteLine();
/////////////////////////////////////////////////////////////////
// Perform the query operation across multiple data tables
//
Console.WriteLine("\nQuery the max grade of each course:\n");
// Perform the query and get an anonymous type collection
var courses = from grade in entities.CourseGrade
group grade by grade.Course.CourseID into g
join cur in entities.Course
on g.Key equals cur.CourseID
select new
{
CourseID = g.Key,
Title = cur.Title,
TopGrade = g.Max(gra => gra.Grade == null ?
decimal.Zero : gra.Grade)
};
// Display the query results
foreach (var c in courses)
{
Console.WriteLine("Course = {0}, TopGrade = {1}", c.Title,
c.TopGrade);
}
Console.WriteLine();
/////////////////////////////////////////////////////////////////
// Perform the query operation across multiple related data
// tables
//
Console.WriteLine("\nQuery all the grades that Nino got:\n");
// Perform the query between related data tables and get an
// anonymous type collection
var grades = from per in entities.Person
from gra in per.CourseGrade
join cur in entities.Course
on gra.Course equals cur
where per.FirstName == "Nino"
select new
{
Person = per,
Course = cur,
CourseGrade = gra
};
// Display the query results
foreach (var grade in grades)
{
Console.WriteLine("FirstName = {0}, Course = {1}, Grade = "
+ "{2}", grade.Person.FirstName, grade.Course.Title,
grade.CourseGrade.Grade);
}
Console.WriteLine();
/////////////////////////////////////////////////////////////////
// Perform the query operation accross Many-to-Many related
// data tables
//
Console.WriteLine("\nQuery all the courses that Jialiang Ge " +
"owns:\n");
// Perform the query across Many-to-Many related data tables and
// get an anonymous type collection
var instructors = from i in entities.Person.OfType <Instructor>()
where i.LastName == "Ge" && i.FirstName ==
"Jialiang"
select new
{
Name = i.FirstName + " " + i.LastName,
Courses = i.Course
};
// Display the query results
foreach (var i in instructors)
{
Console.WriteLine("The instructors {0}'s couses:", i.Name);
foreach (var c in i.Courses)
{
Console.WriteLine("Course Title: {0}, Credits: {1}",
c.Title, c.Credits);
}
}
Console.Read();
}
catch (Exception e)
{
Console.WriteLine("The application throws the error: {0}",
e.Message);
Console.Read();
}
}