Code First Approach in MVC With Entity Framework With Primary and Foreign Key Creation

In my previous article I explained what Code First Approach in MVC with Entity Framework is. Now in this article I will show how to create a Primary Key and Foreign Key using the code first approach in MVC with Entity Framework.

Here I will create 2 tables, Students and Course. Both tables will have a Primary Key and the Student table will reference the course table with CourseID as the Foreign Key.

Now open Visual Studio 2012 and select New Project.

Now right-click on the project in the Solution Explorer then click on Manage NuGet Packages.

Now here in this project I will create 2 tables, one is the Student table and the second one is the Course table. Both tables will have a Primary Key and the Student and Course tables will have a Foreign Key, CourseID. So here I will create 2 clasess in the Model Folder.

Student.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Web;

namespace CodeFirstApproachWithPrimaryForeignKey.Models
{
    public class Student
    {
        public Student()
        {

        }
        [Key]
        public int Id { get; set; }
        public string Name { get; set; }

        [DataType(DataType.Date),
         DisplayFormat(DataFormatString = "{0:dd/MM/yy}",
         ApplyFormatInEditMode = true)]
        public DateTime? DateOfBirth { get; set; }
        public string EmailId { get; set; }
        public string Address { get; set; }
        public string City { get; set; }
        public int CourseId { get; set; }

        public Course Course { get; set; } // Navigation Property

        [NotMapped]
        public string CourseName { get; set; }

    }
}

Here CourseName will not be a field because I set it as NotMapped.

 

Now Course.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Web;

namespace CodeFirstApproachWithPrimaryForeignKey.Models
{
    public class Course
    {
        public Course()
        {

        }
        [Key]
        public int CourseId { get; set; }
        public string CourseName { get; set; }

        public List<Student> Students { get; set; } // Navigation property
    }
}

Now again right-click on the Model folder and add the new class StudentDBContext.cs.

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;
using System.Linq;
using System.Web;

namespace CodeFirstApproachWithPrimaryForeignKey.Models
{
    public class StudentDBContext : DbContext
    {
        public StudentDBContext()
            : base("StudentDbContext")
        {
        }

        public DbSet<Student> Students { get; set; }
        public DbSet<Course> Courses { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Course>().HasKey(p => p.CourseId);
            modelBuilder.Entity<Course>().Property(c => c.CourseId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

            modelBuilder.Entity<Student>().HasKey(b => b.Id);
            modelBuilder.Entity<Student>().Property(b => b.Id)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

            modelBuilder.Entity<Student>().HasRequired(p => p.Course)
                .WithMany(b => b.Students).HasForeignKey(b => b.CourseId);

            base.OnModelCreating(modelBuilder);
        }
    }
}

Here In this StudentDBContext.cs you can see I am using OnModelCreating. Here I define what will be the Primary Key and what will be the Foreign Key.

Now right-click on Controller then select Add -> Controller -> Student.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using CodeFirstApproachWithPrimaryForeignKey.Models;

namespace CodeFirstApproachWithPrimaryForeignKey.Controllers
{
    public class StudentController : Controller
    {
        //
        // GET: /Student/

        StudentDBContext objContext;

        public StudentController()
        {
            objContext = new StudentDBContext();
        }

        #region List and Details student

        public ActionResult Index()
        {
            var students = (from p in objContext.Students
                            join f in objContext.Courses
                        on p.CourseId equals f.CourseId
                            select new
                            {
                                Id = p.Id,
                                Name = p.Name,
                                DateOfBirth = p.DateOfBirth,
                                EmailId = p.EmailId,
                                Address = p.Address,
                                City = p.City,
                                CourseName = f.CourseName
                            }).ToList()
                      .Select(x => new Student()
                      {
                          Id = x.Id,
                          Name = x.Name,
                          DateOfBirth = x.DateOfBirth,
                          EmailId = x.EmailId,
                          Address = x.Address,
                          City = x.City,
                          CourseName = x.CourseName
                      });
            return View(students.ToList());
        }

        public ViewResult Details(int id)
        {
            //Student student = objContext.Students.Where(x => x.Id == id).SingleOrDefault();
            var student = (from p in objContext.Students
                            join f in objContext.Courses
                        on p.CourseId equals f.CourseId
                        where (p.Id==id)
                            select new
                            {
                                Id = p.Id,
                                Name = p.Name,
                                DateOfBirth = p.DateOfBirth,
                                EmailId = p.EmailId,
                                Address = p.Address,
                                City = p.City,
                                CourseName = f.CourseName
                            }).ToList()
                     .Select(x => new Student()
                     {
                         Id = x.Id,
                         Name = x.Name,
                         DateOfBirth = x.DateOfBirth,
                         EmailId = x.EmailId,
                         Address = x.Address,
                         City = x.City,
                         CourseName = x.CourseName
                     }).SingleOrDefault();
            return View(student);
        }

        #endregion

        #region Create student

        public ActionResult Create()
        {
            var data = from p in objContext.Courses
                       select new
                       {
                           CourseID = p.CourseId,
                           CourseName = p.CourseName
                       };

            SelectList list = new SelectList(data, "CourseID", "CourseName");
            ViewBag.Roles = list;

            return View(new Student());
        }

        [HttpPost]
        public ActionResult Create(Student student)
        {
            objContext.Students.Add(student);
            objContext.SaveChanges();
            return RedirectToAction("Index");
        }

        #endregion

        #region Edit student

        public ActionResult Edit(int id)
        {
            var data = from p in objContext.Courses
                       select new
                       {
                           CourseID = p.CourseId,
                           CourseName = p.CourseName
                       };

            SelectList list = new SelectList(data, "CourseID", "CourseName");
            ViewBag.Roles = list;

            Student student = objContext.Students.Where(x => x.Id == id).SingleOrDefault();
            return View(student);
        }


        [HttpPost]
        public ActionResult Edit(Student model)
        {
            Student student = objContext.Students.Where(x => x.Id == model.Id).SingleOrDefault();
            if (student != null)
            {
                objContext.Entry(student).CurrentValues.SetValues(model);
                objContext.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(model);
        }

        #endregion

        #region Delete student

        public ActionResult Delete(int id)
        {
            Student student = objContext.Students.Find(id);
            return View(student);
        }

        [HttpPost]
        public ActionResult Delete(int id, Student model)
        {
            var student = objContext.Students.Where(x => x.Id == id).SingleOrDefault();
            if (student != null)
            {
                objContext.Students.Remove(student);
                objContext.SaveChanges();
            }
            return RedirectToAction("Index");
        }
        #endregion
    }
}

Views Are for Create/Read/Details/Edit/Delete

 

Index.cshtml

<h2>Showing All Students</h2>

<p>
    @Html.ActionLink("Create New", "Create")
</p>
<table style="width:100%;">
   <tr>
        <th >
            @Html.DisplayNameFor(model => model.Name)
        </th>
       <th style="width:20%;">
            @Html.DisplayNameFor(model => model.DateOfBirth)
        </th>
        <th style="width:20%;">
            @Html.DisplayNameFor(model => model.EmailId)
        </th>
       <th>
            @Html.DisplayNameFor(model => model.Address)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.City)
        </th>
      <th>
            @Html.DisplayNameFor(model => model.CourseName)
        </th>
        <th></th>
    </tr>

@foreach (var item in Model) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.Name)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.DateOfBirth)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.EmailId)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Address)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.City)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.CourseName)
        </td>
        <td>
            @Html.ActionLink("Edit", "Edit", new { id=item.Id }) |
            @Html.ActionLink("Details", "Details", new { id=item.Id }) |
            @Html.ActionLink("Delete", "Delete", new { id=item.Id })
        </td>
    </tr>
}

</table>

Create.cshtml

@model CodeFirstApproachWithPrimaryForeignKey.Models.Student

@{
    ViewBag.Title = "Create";
}

<h2>Create</h2>

@using (Html.BeginForm())
{
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>Student</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Name)
            @Html.ValidationMessageFor(model => model.Name)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.DateOfBirth)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.DateOfBirth)
            @Html.ValidationMessageFor(model => model.DateOfBirth)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.EmailId)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.EmailId)
            @Html.ValidationMessageFor(model => model.EmailId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Address)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Address)
            @Html.ValidationMessageFor(model => model.Address)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.City)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.City)
            @Html.ValidationMessageFor(model => model.City)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.CourseId)
        </div>
        <div class="editor-field">
            @Html.DropDownListFor(m=>m.CourseId, ViewBag.Roles as SelectList, "Select ...", new { @class = "myClass", style = "width: 250px;" })

           @* @Html.EditorFor(model => model.CourseId)*@
            @Html.ValidationMessageFor(model => model.CourseId)
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

Delete.cshtml

@model CodeFirstApproachWithPrimaryForeignKey.Models.Student

@{
    ViewBag.Title = "Delete";
}

<h2>Delete</h2>

<h3>Are you sure you want to delete this?</h3>
<table>
    <tr>
        <td>@Html.DisplayNameFor(model => model.Name)</td>
        <td>@Html.DisplayFor(model => model.Name)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.DateOfBirth)</td>
        <td>@Html.DisplayFor(model => model.DateOfBirth)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.EmailId)</td>
        <td>@Html.DisplayFor(model => model.EmailId)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.Address)</td>
        <td>@Html.DisplayFor(model => model.Address)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.City)</td>
        <td>@Html.DisplayFor(model => model.City)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.CourseName)</td>
        <td>@Html.DisplayFor(model => model.CourseName)</td>
    </tr>

    <tr style="background-color: orange; padding: 25px;">
        <td></td>
        <td>@Html.ActionLink("Edit", "Edit", new { id = Model.Id }) |
    @Html.ActionLink("Back to List", "Index")</td>

    </tr>
</table>

@using (Html.BeginForm())
{
    <table>
        <tr style="background-color: orange; padding: 25px;">
            <td></td>
            <td>
                <input type="submit" value="Delete" />

                @Html.ActionLink("Back to List", "Index")
            </td>

        </tr>
    </table>
}

Details.cshtml

@model CodeFirstApproachWithPrimaryForeignKey.Models.Student

@{
    ViewBag.Title = "Details";
}

<h2>Details Of Student</h2>


<table>
    <tr>
        <td>@Html.DisplayNameFor(model => model.Name)</td>
        <td>@Html.DisplayFor(model => model.Name)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.DateOfBirth)</td>
        <td>@Html.DisplayFor(model => model.DateOfBirth)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.EmailId)</td>
        <td>@Html.DisplayFor(model => model.EmailId)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.Address)</td>
        <td>@Html.DisplayFor(model => model.Address)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.City)</td>
        <td>@Html.DisplayFor(model => model.City)</td>
    </tr>
    <tr>
        <td>@Html.DisplayNameFor(model => model.CourseName)</td>
        <td>@Html.DisplayFor(model => model.CourseName)</td>
    </tr>

    <tr style="background-color: orange; padding: 25px;">
        <td></td>
        <td>@Html.ActionLink("Edit", "Edit", new { id = Model.Id }) |
    @Html.ActionLink("Back to List", "Index")</td>

    </tr>
</table>

Edit.cshtml

@model CodeFirstApproachWithPrimaryForeignKey.Models.Student

@{
    ViewBag.Title = "Edit";
}

<h2>Edit</h2>

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>Student</legend>

        @Html.HiddenFor(model => model.Id)

        <div class="editor-label">
            @Html.LabelFor(model => model.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Name)
            @Html.ValidationMessageFor(model => model.Name)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.DateOfBirth)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.DateOfBirth)
            @Html.ValidationMessageFor(model => model.DateOfBirth)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.EmailId)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.EmailId)
            @Html.ValidationMessageFor(model => model.EmailId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Address)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Address)
            @Html.ValidationMessageFor(model => model.Address)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.City)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.City)
            @Html.ValidationMessageFor(model => model.City)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.CourseId)
        </div>
        <div class="editor-field">
             @Html.DropDownListFor(m=>m.CourseId, ViewBag.Roles as SelectList, "Select ...", new { @class = "myClass", style = "width: 250px;" })

           @* @Html.EditorFor(model => model.CourseId)*@
            @Html.ValidationMessageFor(model => model.CourseId)
        </div>

        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

Now again right-click on Controller then select Add-> Controller -> Course.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using CodeFirstApproachWithPrimaryForeignKey.Models;

namespace CodeFirstApproachWithPrimaryForeignKey.Controllers
{
    public class CourseController : Controller
    {
        //
        // GET: /Course/

        StudentDBContext objContext;
        public CourseController()
        {
            objContext = new StudentDBContext();
        }

        #region List and Details course

        public ActionResult Index()
        {
            var courses = objContext.Courses.ToList();
            return View(courses);
        }

        public ViewResult Details(int id)
        {
            Course course = objContext.Courses.Where(x => x.CourseId == id).SingleOrDefault();
            return View(course);
        }

        #endregion

        #region Create course

        public ActionResult Create()
        {
            return View(new Course());
        }

        [HttpPost]
        public ActionResult Create(Course course)
        {
            objContext.Courses.Add(course);
            objContext.SaveChanges();
            return RedirectToAction("Index");
        }

        #endregion

        #region edit course

        public ActionResult Edit(int id)
        {
            Course course = objContext.Courses.Where(x => x.CourseId == id).SingleOrDefault();
            return View(course);
        }


        [HttpPost]
        public ActionResult Edit(Course model)
        {
            Course course = objContext.Courses.Where(x => x.CourseId == model.CourseId).SingleOrDefault();
            if (course != null)
            {
                objContext.Entry(course).CurrentValues.SetValues(model);
                objContext.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(model);
        }

      #endregion

        #region Delete course
        public ActionResult Delete(int id)
        {
            Course course = objContext.Courses.Find(id);
            return View(course);
        }

        [HttpPost]
        public ActionResult Delete(int id, Course model)
        {
            var course = objContext.Courses.Where(x => x.CourseId == id).SingleOrDefault();
            if (course != null)
            {
                objContext.Courses.Remove(course);
                objContext.SaveChanges();
            }
            return RedirectToAction("Index");
        }
        #endregion

    }
}

View for Course

Index.cshtml

@model IEnumerable<CodeFirstApproachWithPrimaryForeignKey.Models.Course>

@{
    ViewBag.Title = "Index";
}

<h2>Index</h2>

<p>
    @Html.ActionLink("Create New", "Create")
</p>
<table>
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.CourseName)
        </th>
        <th></th>
    </tr>

@foreach (var item in Model) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.CourseName)
        </td>
        <td>
            @Html.ActionLink("Edit", "Edit", new { id=item.CourseId }) |
            @Html.ActionLink("Details", "Details", new { id=item.CourseId }) |
            @Html.ActionLink("Delete", "Delete", new { id=item.CourseId })
        </td>
    </tr>
}

</table>

Create.cshtml

@model CodeFirstApproachWithPrimaryForeignKey.Models.Course

@{
    ViewBag.Title = "Create";
}

<h2>Create</h2>

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>Course</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.CourseName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.CourseName)
            @Html.ValidationMessageFor(model => model.CourseName)
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

Delete.cshtml

model CodeFirstApproachWithPrimaryForeignKey.Models.Course

@{
    ViewBag.Title = "Delete";
}

<h2>Delete</h2>

<h3>Are you sure you want to delete this?</h3>
<fieldset>
    <legend>Course</legend>

    <div class="display-label">
         @Html.DisplayNameFor(model => model.CourseName)
    </div>
    <div class="display-field">
        @Html.DisplayFor(model => model.CourseName)
    </div>
</fieldset>
@using (Html.BeginForm()) {
    <p>
        <input type="submit" value="Delete" /> |
        @Html.ActionLink("Back to List", "Index")
    </p>
}

Details.cshtml

@model CodeFirstApproachWithPrimaryForeignKey.Models.Course

@{
    ViewBag.Title = "Details";
}

<h2>Details</h2>

<fieldset>
    <legend>Course</legend>

    <div class="display-label">
         @Html.DisplayNameFor(model => model.CourseName)
    </div>
    <div class="display-field">
        @Html.DisplayFor(model => model.CourseName)
    </div>
</fieldset>
<p>
    @Html.ActionLink("Edit", "Edit", new { id=Model.CourseId }) |
    @Html.ActionLink("Back to List", "Index")
</p>

Edit.cshtml

@model CodeFirstApproachWithPrimaryForeignKey.Models.Course

@{
    ViewBag.Title = "Edit";
}

<h2>Edit</h2>

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>Course</legend>

        @Html.HiddenFor(model => model.CourseId)

        <div class="editor-label">
            @Html.LabelFor(model => model.CourseName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.CourseName)
            @Html.ValidationMessageFor(model => model.CourseName)
        </div>

        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

Run the Application

Now see your database:

Click on Course then select Create New.

Showing All Course List:

Click on Edit Course:

Details of a course:

Delete an existing Course:

Now click on Student-> Create New.

List of all students.

Edit any student record:

Details of any student:

Delete any student record:

Now see your database. See the records in both tables and see the Primary Key and Foreign Key existence:

If you want to run this application in your machine then just change the connection string in the web.config file.