Many developers has confusion on how to write database code in application. I will discuss several approaches here and try to provide explanation on each approach. Approach 1 : Easiest approach which is very straight forward which will work absolutely fine. The issues we will get to manage the project in terms of software principles. Like if you going to change Database provider, you would need to change using statements and other issue like mixing Database code with business logic etc. I will not go in detail here, I am assuming you already have an understanding of design principles. I am just exploring different approaches to achieve the database connectivity. using System.Collections.Generic; using System.Data.SqlClient; namespace DatabaseFactory { class Program { static void Main(string[] args) { var employees = SomeDabOperation(); } private static List<Employee> SomeDabOperation() { u