Create table in Database using Entity Framework

Question

I'm trying to link my MVC project with a database using Entity Framework, but I can't figure out how to store new records to a database. So far I have the following code:

//model

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using MvcApplication1.Controllers;

namespace MvcApplication1.Models
{
public class CarUser
{
    public int ID { get; set; }
    [DisplayName ("First Name")]
    public string Fname { get; set; }
    [DisplayName ("Surname")]
    public string Sname { get; set; }
}
}

//controller

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using MvcApplication1.Models;

namespace MvcApplication1.Controllers
{
public class CarUserController : Controller
{
    private FormDataContext db = new FormDataContext();

    //
    // GET: /CarUser/

    public ActionResult Index()
    {
        return View(db.CarUsers.ToList());
    }

    //
    // GET: /CarUser/Details/5

    public ActionResult Details(int id = 0)
    {
        CarUser caruser = db.CarUsers.Find(id);
        if (caruser == null)
        {
            return HttpNotFound();
        }
        return View(caruser);
    }

    //
    // GET: /CarUser/Create

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

    //
    // POST: /CarUser/Create

    [HttpPost]
    public ActionResult Create(CarUser caruser)
    {
        if (ModelState.IsValid)
        {
            db.CarUsers.Add(caruser);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        return View(caruser);
    }

    //
    // GET: /CarUser/Edit/5

    public ActionResult Edit(int id = 0)
    {
        CarUser caruser = db.CarUsers.Find(id);
        if (caruser == null)
        {
            return HttpNotFound();
        }
        return View(caruser);
    }

    //
    // POST: /CarUser/Edit/5

    [HttpPost]
    public ActionResult Edit(CarUser caruser)
    {
        if (ModelState.IsValid)
        {
            db.Entry(caruser).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
        }
        return View(caruser);
    }

    //
    // GET: /CarUser/Delete/5

    public ActionResult Delete(int id = 0)
    {
        CarUser caruser = db.CarUsers.Find(id);
        if (caruser == null)
        {
            return HttpNotFound();
        }
        return View(caruser);
    }

    //
    // POST: /CarUser/Delete/5

    [HttpPost, ActionName("Delete")]
    public ActionResult DeleteConfirmed(int id)
    {
        CarUser caruser = db.CarUsers.Find(id);
        db.CarUsers.Remove(caruser);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    protected override void Dispose(bool disposing)
    {
        db.Dispose();
        base.Dispose(disposing);
    }
}
}

//formdatacontext

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;

namespace MvcApplication1.Models
{
public class FormDataContext : DbContext
{
    public DbSet<CarUser> CarUsers
    { get; set; }
}
}

//formdatainitialiser

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;
using System.IO;

namespace MvcApplication1.Models
{
public class FormDataInitializer : DropCreateDatabaseAlways<FormDataContext>
{
    protected override void Seed(FormDataContext context)
    {
        base.Seed(context);

        var CarUsers = new List<CarUser>
        {
            new CarUser {
                ID = 1,
                Fname = "Craig",
                Sname = "Higginson",
            }
        };

        CarUsers.ForEach(s => context.CarUsers.Add(s));
        context.SaveChanges();

        }
    }

}

I've also got the following in my web.config file

<connectionStrings>
<add name="FormDataContext"
     connectionString="Data Source=.\SQLEXPRESS;Initial Catalog=FormData.mdf;Integrated Security=True" providerName="System.Data.SqlClient" />

This all builds fine, and when I navigate to /caruser i am able to create new records. These records aren't being stored in my database.

Do I need to create the table in the database first or should Entity Framework create this for me, if i have referenced the database correctly?

Mike Marks · Accepted Answer · 2013-12-09 16:23:03Z

1

If you're using a Code First approach then Entity Framework will build the table for you. It looks like you are not using Code First, so you will have create the table in the database. I assume you're using an Entity Data Model (.edmx)? If so, you will create your table in the database, then update your data model (.edmx). If you have not yet created your .edmx file, you need to do that - the .edmx file will contain all your CRUD operations.

What I'm confused about is I'd imagine your code would throw an error if the table did not exist (i.e. if the table represented by your data model didn't map to an actual table in the database, because it doesn't exist). So, the question is, does your table already exist? If it does, then step through the code line by line to find out why your records aren't being saved. If it doesn't exist, then add the table via SQL Server Management Studio (or similar), then open your .edmx file, right click on the layout that comes up, click "Update Model from database".

edited Dec 9, 2013 at 16:23

answered Dec 9, 2013 at 16:14

Mike Marks

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1 Comment

user1894555 Over a year ago

to be fair, im not 100% sure what ive done, but its sorted now. I think my table already existed, i was just looking in the wrong place? Thanks for you help

d.lavysh · Accepted Answer · 2013-12-09 16:15:00Z

1

You can find all needed info here: creating-an-entity-framework-data-model-for-an-asp-net-mvc-application

answered Dec 9, 2013 at 16:15

d.lavysh

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Comments

user3094403 · Accepted Answer · 2015-11-29 15:17:20Z

0

First you have add an edmx project to your existing solution which is a mockup of db and contains all the tables and SPs.
From your action method make a call to one more class, say DataAccessLayer.cs.
In DataAccessLayer.cs, add a reference to your edmx project.

Use this code:

using (var entity = new FormDataContext()) 
{
    //entity. will give you all the tables in the database.
}

edited Nov 29, 2015 at 15:17

user3094403

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answered Dec 10, 2013 at 7:35

user1400915

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6 Comments

Mike Marks Over a year ago

This isn't addressing his problem. You showed how to essentially add an Entity Data Model project. His issue was that the data wasn't being stored in the database. Based on his code sample, it appears he's already added an .edmx data model in MvcApplication1.Models but for some reason his data is not being stored in the database.

Mike Marks Over a year ago

And it also appears he's using MVC, so why would he create a separate DataAccessLayer.cs class to query his data, when he would normally do that in the controller code? By the way, the data access layer in this case is the Entity Data Model code behind, so DataAccessLayer.cs, in my opinion, isn't a good name.

CSharper Over a year ago

@Mike, database queries should NEVER be done in the controller.

The incredible Jan Over a year ago

@CSharper What do/did you mean? The "real" queries are done by the Entity Framework but the purpose of a controller is to communicate wiht the database layer by the Entity Framework. Mike Marks is 100% right.

NOCARRIER Over a year ago

Saying something should "never" be done in programming is a bit myopic and imho demonstrates a lack of experience. There are lots and lots of different patterns which do all kinds of things you should "never do" very well.

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