LINQ To Entity Framework Tutorial – Part II

In this post, I am going to explain below operations in LINQ.

1. Sorting
   
2. Group By
   
3. Left Join

1) Sorting: Ascending:

Employee[] AllEmployees = (from E in NorthwindEntity.Employees
orderby E.FirstName ascending
select E).ToArray();

Descending:

Employee[] AllEmployees = (from E in NorthwindEntity.Employees
orderby E.FirstName descending
select E).ToArray();

2) Group By:

var AllEmployee = from E in NorthwindEntity.Employees
group E by E.LastName into G
select new { LastName = G.Key, Group = G };

foreach (var employees in AllEmployee)
{
// employees.Group is the current group 
// Here you will find each group ( using employees.Group ) for employees.LastName

foreach (var employee in employees.Group)
{
// Here you will find each employee in particular group
// You can access each property of Employee object here.
}
}

3) Left Join:

var allProductsWithCategory = from p in NorthwindEntity.Products
let c = (from c in NorthwindEntity.Categories
where c.CategoryID == p.CategoryID
select c).FirstOrDefault()
select new { Productname = p.ProductName, CategoryName = c.CategoryName };

foreach (var item in allProductsWithCategory)
{

// You will find product's name and category row by row here...
// item.Productname
// item.CategoryName;

}

That’s all for today’s post, In my next post I will try to upload demo project to understand LINQ more.
For next post I have two topics in my mind:

1. Using lambda expressions
   
2. Bulk insert / update / delete operations