Data Context and Db Set -- MVC Basics

DbContext: Simplified alternative to Object Context and is the primary object for interacting with a database using a specific model. 

DbSet : Simplified alternative to Object Set and is used to perform CRUD operations against a specific type from the model.

DbContext and DbSet is used for the Code First appraoch.Which enables a very clean and rapid development workflow.

Suppose we want to create a database called 'New Database' and two tables in that called 'State' and 'Country’. Then write the Model classes..

Go to Models right click on Models>>Add>>Class

Add a model class and name it as Country.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.ComponentModel.DataAnnotations;

namespace MvcApplication2.Models

{

    public class Country

    {

        [Key]

        public virtual int country_id {get; set; }

        [Required ]

        public virtual string country_name { get; set;}

    }

}

Similarly add another class and named it as State.cs.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.ComponentModel.DataAnnotations;

namespace MvcApplication2.Models

{

    public class State

    {

        [Key]

        public virtual int state_id {get; set; }

        [Required ]

        public virtual string state_name { get; set;}

    }

}

Add another Model class 'New Database.cs'

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Data.Entity;

namespace MvcApplication2.Models

{

    public class NewDatabase:DbContext

    {

        public DbSet Country { get; set; }

        public DbSet State { get; set; }

    }

}

Run 'Enable-Migrations' command from Package Manager Console

Open Configuration file and set AutomaticMigrationsEnabled = true;
2. Then run 'Update-Database' command from Package Manager Console

 Now tables will get created as per given model.