private static void EfExtensionsDelete(SoftUniEntities context)
{
context.Images
.Where(i => i.ImageBase64.EndsWith("6"))
.Delete();
context.SaveChanges();
}
private static void EfExtensionsUpdate(SoftUniEntities context)
{
context.Employees
.Update(e => new Employee()
{
Salary = 850000
});
context.SaveChanges();
}
private static void EfStandartUpdate(SoftUniEntities context)
{
var employees = context.Employees;
foreach (var employee in employees)
{
employee.Salary = 520000;
}
context.SaveChanges();
}
private static void EfStandartDelete(SoftUniEntities context)
{
var images = context.Images
.Where(i => i.ImageBase64.EndsWith("5"));
foreach (var image in images)
{
context.Images.Remove(image);
}
context.SaveChanges();
}
static void Main()
{
// // Test connection:
//using (var context = new SoftUniEntities())
//{
// var employees = context.Employees
// .Where(e => e.Department.Name == "Engineering")
// .Select(e => new
// {
// e.FirstName,
// e.LastName,
// Department = e.Department.Name
// });
// foreach (var employee in employees)
// {
// Console.WriteLine("{0} {1} --- {2}", employee.FirstName, employee.LastName, employee.Department);
// }
//}
// // Multiple SQL Requests:
//using (var context = new SoftUniEntities())
//{
// var employees = context.Employees;
// foreach (var employee in employees)
// {
// Console.WriteLine("{0} {1} {2}", employee.LastName, employee.Department.Name, employee.Address.Town.Name);
// }
//}
// // A single SQL request
//using (var context = new SoftUniEntities())
//{
// var employees = context.Employees
// .Select(e => new
// {
// e.LastName,
// Department = e.Department.Name,
// Town = e.Address.Town.Name
// });
// foreach (var employee in employees)
// {
// Console.WriteLine("{0} {1} {2}", employee.LastName, employee.Department, employee.Town);
// }
//}
// Another way for the above, but less efficient:
//using (var context = new SoftUniEntities())
//{
// foreach (var employee in context.Employees
// .Include(e => e.Department)
// .Include(e => e.Address.Town))
// {
// Console.WriteLine("{0} {1} {2}", employee.LastName, employee.Department.Name, employee.Address.Town.Name);
// }
//}
//using (var context = new SoftUniEntities())
//{
// var towns = context.Towns
// .Select(t => new
// {
// t.Name,
// t.TownID
// });
// foreach (var town in towns)
// {
// Console.WriteLine("{0}, {1}", town.TownID, town.Name);
// }
//}
//using (var context = new SoftUniEntities())
//{
// var employees = context.Employees
// .OrderByDescending(e => e.FirstName)
// .Take(3);
// foreach (var employee in employees)
// {
// Console.WriteLine("name: {0} department: {1} town: {2}",
// employee.LastName,
// employee.Department.Name,
// employee.Address.Town.Name);
// }
//}
//using (var context = new SoftUniEntities())
//{
// var employees = context.Employees
// .OrderByDescending(e => e.LastName)
// //YOU CAN ONLY INCLUDE WHOLE TABLES!
// .Include(e => e.Department)
// .Include(e => e.Address.Town)
// .Take(3);
// foreach (var employee in employees)
// {
// Console.WriteLine("name: {0} department: {1} town: {2}",
// employee.LastName,
// employee.Department.Name,
// employee.Address.Town.Name);
// }
//}
//using (var context = new SoftUniEntities())
//{
// var employees = context.Employees
// .OrderByDescending(e => e.LastName)
// .Include(e => e.Department)
// .Include(e => e.Address.Town)
// .Take(3)
// .Select(e => new
// {
// e.LastName,
// Department = e.Department.Name,
// Town = e.Address.Town.Name
// });
// foreach (var employee in employees)
// {
// Console.WriteLine("name: {0} department: {1} town: {2}",
// employee.LastName,
// employee.Department,
// employee.Town);
// }
//}
// //Correct use of .ToList()
//using (var context = new SoftUniEntities())
//{
// var employeesFromRedmond = context.Employees
// .Where(e => e.Address.Town.Name == "Redmond")
// .Select(e => new
// {
// e.FirstName,
// e.LastName,
// e.JobTitle,
// e.Address.AddressText
// })
// .OrderBy(e => e.LastName)
// .ToList();
// foreach (var emp in employeesFromRedmond)
// {
// Console.WriteLine("{0} {1} ({2}), address: {3}", emp.FirstName, emp.LastName, emp.JobTitle, emp.AddressText);
// }
//}
//using (var context = new SoftUniEntities())
//{
// var employeesFromCalgary = context.Employees
// //INCORRECT, SHOULD BE AT THE END!!!
// .ToList()
// .Where(e => e.Address.Town.Name == "Calgary")
// .Select(e => new
// {
// e.FirstName,
// e.LastName,
// e.JobTitle,
// e.Address.AddressText
// })
// .OrderBy(e => e.LastName);
// foreach (var emp in employeesFromCalgary)
// {
// Console.WriteLine("{0} {1} ({2}), address: {3}", emp.FirstName, emp.LastName, emp.JobTitle, emp.AddressText);
// }
//}
//using (var context = new SoftUniEntities())
//{
// decimal totalSalaries = 0;
// foreach (var salary in context.Employees
// {
// totalSalaries += salary;
// }
// Console.WriteLine("{0:F2}", totalSalaries);
//}
//using (var context = new SoftUniEntities())
//{
// decimal totalSalaries = 0;
// foreach (var salary in context.Employees
// .Select(e => e.Salary))
// {
// totalSalaries += salary;
// }
// Console.WriteLine("{0:F2}", totalSalaries);
//}
//using (var context = new SoftUniEntities())
//{
// var totalSalaries = context.Employees
// .Sum(e => e.Salary);
// var avgSalaries = context.Employees
// .Average(e => e.Salary);
// Console.WriteLine("Total salaries: {0:F2}", totalSalaries);
// Console.WriteLine("Average salary: {0:F2}", avgSalaries);
//}
//using (var context = new SoftUniEntities())
//{
// var employeesProjects = context.Employees
// .Where(e => e.Address.Town.Name == "Redmond")
// .Select(e => new
// {
// e.FirstName,
// e.LastName,
// Town = e.Address.Town.Name,
// Department = e.Department.Name,
// Manager = e.Manager.LastName,
// Projects = e.Projects.Select(p => new
// {
// Project = p.Name,
// p.Description,
// AvgSalary = p.Employees.Average(emp => emp.Salary)
// })
// })
// .Take(10)
// .OrderByDescending(e => e.Department)
// .ToList();
// foreach (var emp in employeesProjects)
// {
// Console.WriteLine("----- {0} {1} from {2}, department: {3}, manager: {4}", emp.FirstName, emp.LastName, emp.Town, emp.Department, emp.Manager);
// foreach (var project in emp.Projects)
// {
// Console.WriteLine("{0}, average employee salary: {1}", project.Project, project.AvgSalary);
// }
// }
//}
// UPDATING Entities in EF
//using (var context = new SoftUniEntities())
//{
// var timer = new Stopwatch();
// timer.Start();
// EfStandartUpdate(context);
// Console.WriteLine("EF query: {0}", timer.Elapsed); //00:00:00.2239094
// timer.Restart();
// timer.Start();
// NativeUpdate(context);
// Console.WriteLine("Native query: {0}", timer.Elapsed); //00:00:00.0046463
//}
// UPDATING Entities with EF Extensions
//using (var context = new SoftUniEntities())
//{
// context.Employees
// .Where(e => e.FirstName == "Jacomo")
// .Update(e => new Employee()
// {
// FirstName = "Roberto"
// });
// context.SaveChanges();
//}
//using (var context = new SoftUniEntities())
//{
// context.Employees
// .Update(e => new Employee()
// {
// Salary = 600000
// });
// context.SaveChanges();
//}
// DELETING WITH EF Extensions
//using (var context = new SoftUniEntities())
//{
// var employees = context.Employees
// .Where(e => e.Address.Town.Name == "Sofia")
// .Select(e => new
// {
// e.FirstName,
// e.LastName,
// Address = e.Address.AddressText,
// Town = e.Address.Town.Name
// });
// foreach (var employee in employees)
// {
// Console.WriteLine("{0} {1} --- {2}, {3}", employee.FirstName, employee.LastName, employee.Address, employee.Town);
// }
// context.Employees
// .Where(e => e.Address.Town.Name == "Sofia")
// .Delete();
// context.SaveChanges();
//}
// Comparing the three different update methods Speed:
//using (var context = new SoftUniEntities())
//{
// var employeesCount = context.Employees.Count();
// Console.WriteLine("Number of employees: {0}", employeesCount);
// Stopwatch timer = new Stopwatch();
// timer.Start();
// EfStandartUpdate(context);
// Console.WriteLine("EF Standard update: {0}", timer.Elapsed);
// timer.Restart();
// EfExtensionsUpdate(context);
// Console.WriteLine("EF Extensions update: {0}", timer.Elapsed);
// timer.Restart();
// NativeUpdate(context);
// Console.WriteLine("Native update: {0}", timer.Elapsed);
//}
//Add a Base64 Encoded image to the database:
using (var context = new SoftUniEntities())
{
for (int i = 0; i < 10000; i++)
{
context.Images.Add(new Image()
{
ImageBase64 = new string('-', 5) + i
});
}
context.SaveChanges();
var imageCount = context.Images.Count();
Console.WriteLine(imageCount);
var timer = new Stopwatch();
timer.Start();
EfStandartDelete(context);
Console.WriteLine("EF Standard delete: {0}", timer.Elapsed);
timer.Restart();
EfExtensionsDelete(context);
Console.WriteLine("EF Extensions delete: {0}", timer.Elapsed);
timer.Restart();
NativeDelete(context);
Console.WriteLine("Native delete: {0}", timer.Elapsed);
timer.Restart();
}
}
private static void NativeUpdate(SoftUniEntities context)
{
var query = @"UPDATE Employees SET Salary = 250000";
context.Database.ExecuteSqlCommand(query);
context.SaveChanges();
}
private static void NativeDelete(SoftUniEntities context)
{
var query = @"DELETE FROM Images WHERE Images.ImageBase64 LIKE '%3'";
context.Database.ExecuteSqlCommand(query);
context.SaveChanges();
}