In the simplest form a relation in SQL is matching data in key columns with the same name in different tables. There are three types of relationships between tables. 

One-to-Many Relationship

Many-to-Many Relationships

One-to-One Relationships


One-to-Many Relationships

it is the most common type of relationship. In this type of relationship, a row in table A can have many matching rows in table B, but a row in table B can have only one matching row in t

Liskov substitution principle (LSP) is a simple pattern in object oriented programming ,notice about definition If A is a subtype of B, then object of B could be replaced with object of A, in other definition subclass  can behave like base class. maybe you are using it for years, take a look at  the example:

  1.     public class BaseClass
  2.     {
  3.         public string ProductName { get; set; }
  4.         public Continue

I'm going to write about basic concepts of Microsoft  SQl Server in two part this is the part one! , as I've rarely seen SQL graphical text tutorial (most of them are text only and it does not make good sense for beginners like me), I want to fit more and more picture in this Article! This article is about SQl language fundamentals , and obviously it is familiar for most of the developers!

Introduction to SQl language 

SQL is a language designed to retrieve and management of data in relational databases , SQL is a language and not all r

 What is Entity framework !?

MSDN answers to this question :"Entity Framework is an Object Relational Mapper (ORM). It basically generates business objects and entities according to the database tables provides ability to do CRUD operations , relations and etc."

And also about wikipedia's definition : "The Entity Framework is a se