Unable to access data in an ASP.NET MVC web application using Entity Framework and SQL Server database

In an ASP.NET MVC web application, I have created the following entity:

[Table("tblEmployee")]
public class Employee
{
    public int EmployeeId { get; set; }
    public string Name { get; set; }
    public string Gender { get; set; }
    public string City { get; set; }
}

But, when I try to retrieve data from a database table called tblEmployee using Entity Framework, I get an error. What I have done until now is:

• Created a database MVCDemo with "." as server name and using Windows authentication containing a table called tblEmployee
• Installed Entity Framework
• Added EmployeeContext.cs class file to Models folder

Code:

namespace MVCDemo.Models
{
    public class EmployeeContext : DbContext
    {
        public DbSet<Employee> Employees { get; set; }
    }
} 

• Added a connection string to web.config file in the root directory

   <connectionSrtings>
       <add name="EmployeeContext" 
            connectionString="server=.; database=MVCDemo; integrated security=SSPI"
            providerName="System.Data.SqlClient;" />
   </connectionSrtings>
  

• Added Details actionResult to EmployeeController to show employee details:

    namespace MVCDemo.Controllers
    {
        public class EmployeeController : Controller
        {
            // GET: Employee
            public ActionResult Details(int id)
            {
                EmployeeContext employeeContext = new EmployeeContext();
                Employee employee = employeeContext.Employees.Single(e => e.EmployeeId == id);
                return View(employee);
            }
        }
    }
  

Finally, I added the following code to Global.asax to prevent initialization:

Database.SetInitializer<MVCDemo.Models.EmployeeContext>(null);

The problem is when I run the application I get this error:

HTTP Error 500.19 - Internal Server Error

The requested page cannot be accessed because the related configuration data for the page is invalid.

and when I comment connection strings out and try to reach

http://localhost:60613/Employee/Details/1 

to show details of 1st employee, I get this error:

System.Data.Entity.Core.EntityException: 'The underlying provider failed on Open.'SqlException: Cannot attach the file 'C:\Users\arya\source\repos\MVCDemo\MVCDemo\App_Data\MVCDemo.Models.EmployeeContext.mdf' as database 'MVCDemo.Models.EmployeeContext'.