private static void Delete()
{
var context = new PlutoContext();
var course = context.Courses.Find(6);
context.Courses.Remove(course);
context.SaveChanges();
}
private static void Update()
{
var context = new PlutoContext();
var course = context.Courses.Find(4);
course.Name = "New Name";
course.AuthorId = 2;
context.SaveChanges();
}
private static void DeleteMany()
{
var context = new PlutoContext();
var author = context.Authors.Include(a => a.Courses).Single(a => a.Id == 2);
context.Courses.RemoveRange(author.Courses);
context.Authors.Remove(author);
context.SaveChanges();
}
private static void ChangeTracker()
{
var context = new PlutoContext();
context.Authors.Add(new Author {
Name = "New Author"
});
var entries = context.ChangeTracker.Entries();
foreach (var entry in entries)
{
entry.Reload();
Console.WriteLine(entry.State);
}
}
private static void AddCourse()
{
var context = new PlutoContext();
var author = context.Authors.Single(a => a.Id == 1);
var course = new Course
{
Name = "New Course 2",
Title = "Some Title 2",
Description = "New Description 2",
FullPrice = 19.95f,
Level = CourseLevel.Beginner,
Author = author
};
context.Courses.Add(course);
context.SaveChanges();
}
static void Main(string[] args)
{
var context = new PlutoContext();
// LINQ syntax
var query = from c in context.Courses
where c.Name.Contains("c#")
orderby c.Name
select c;
foreach (var course in query)
{
Console.WriteLine(course.Name);
}
// Extension methods
var courses = context.Courses.Where(c => c.Name.Contains("c#")).OrderBy(c => c.Name);
foreach (var course in courses)
{
Console.WriteLine("COURSE - {0}", course.Name);
}
var queryable = context.Courses.Join(context.Authors, c => c.AuthorId, a => a.Id, (course, author) => new
{
CourseName = course.Name,
AuthorName = author.Name
});
foreach (var q in queryable)
{
Console.WriteLine(q);
}
// Partitioning
context.Courses.Skip(10).Take(10);
// Element operators
context.Courses.First();
context.Courses.FirstOrDefault(c => c.FullPrice > 100);
context.Courses.OrderBy(c => c.Level).Last(c => c.FullPrice > 100);
context.Courses.SingleOrDefault(c => c.Id == 1);
// Quantifying
var all = context.Courses.All(c => c.FullPrice > 10);
var any = context.Courses.Any(c => c.FullPrice > 10);
// Aggregating
context.Courses.Count();
context.Courses.Average(c => c.FullPrice);
context.Courses.Sum(c => c.FullPrice);
context.Courses.Min(c => c.FullPrice);
context.Courses.Max(c => c.FullPrice);
// IQueryable
IQueryable <Course> courses2 = context.Courses;
var filtered = courses2.Where(c => c.Level == (CourseLevel)1);
foreach (var course in filtered)
{
Console.WriteLine(course);
}
IEnumerable <Course> x = context.Courses;
x.Where(c => c.Level == (CourseLevel)1).OrderBy(c => c.Name);
// Lazy loading problem n + 1 issue
// var course3 = context.Courses.ToList();
// foreach (var c in course3)
// {
// Console.WriteLine("{0}, by {1}", c.Name, c.Author.Name);
// }
// Eager loading
var course4 = context.Courses.Include(c => c.Author).ToList();
foreach (var c in course4)
{
Console.WriteLine("{0}, by {1}", c.Name, c.Author.Name);
}
// Explicit loading
var author = context.Authors.Single(a => a.Id == 1);
// MSDN way
context.Entry(author).Collection(a => a.Courses).Load();
// Mosh way
context.Courses.Where(c => c.AuthorId == author.Id).Load();
foreach (var c in author.Courses)
{
Console.WriteLine("{0}", c.Name);
}
var authors2 = context.Authors.ToList();
var ids = authors2.Select(a => a.Id);
context.Courses.Where(c => ids.Contains(c.AuthorId) && c.FullPrice == 0).Load();
// Insert Actions
AddCourse();
// Repository
using var unitOfWork = new UnitOfWork(new PlutoContext());
{
var course = unitOfWork.Courses.Get(1);
var courses7 = unitOfWork.Courses.GetCoursesWithAuthors(1, 4);
}
}
