Retrieve data from sql in MVC 4 - asp.net-mvc

Question

Platfrom : MVC4
Hi,
I am new to MVC4 and I am trying to retrieve the data from SQL using Entity framework, but it fails. Here is the code I have tried so far :
Model: MovieListing.cs
[Table("MovieMaster")]
public class MoviesListing
{
public int MovieId { get; set; }
public string Name { get; set; }
public string year { get; set; }
public string Image { get; set; }
public string producer { get; set; }
public string plot { get; set; }
}
Model:
public class MovieContext:DbContext
{
public DbSet<MoviesListing> Movies { get; set; }
}
View :
#model MovieManiac.Models.MoviesListing
#{
ViewBag.Title = "Moviedetails";
}
<h2>Moviedetails</h2>
<table>
<tr>
<td>Movie Name</td>
<td> #Model.Moviename</td>
</tr>
</table>
Controller:
public ActionResult MovieDetails(int id)
{
MovieContext objMovies = new MovieContext();
MoviesListing movie = objMovies.Movies.Single(mov => mov.MovieId == id);
return View(movie);
}
So, in the browser, when I enter the Id, I want to retrieve information from database.I am using local sql db. Any suggestions?
Connection String:
</configSections>
<connectionStrings>
<add name="MovieContext" providerName="System.Data.SqlClient" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=aspnet-MovieManiac-20150318225934;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnet-MovieManiac-20150318225934.mdf" />
</connectionStrings>
error:
An exception of type 'System.Data.Entity.ModelConfiguration.ModelValidationException' occurred in EntityFramework.dll but was not handled in user code
Additional information: One or more validation errors were detected during model generation:
\tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'MoviesListing' has no key defined. Define the key for this EntityType.
\tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'Movies' is based on type 'MoviesListing' that has no keys defined.

Answer 1

You need to add the Key attribute to the I'd property so EF knows what is the primary key
https://msdn.microsoft.com/en-us/data/jj591583.aspx
http://www.entityframeworktutorial.net/code-first/key-dataannotations-attribute-in-code-first.aspx
Update
You may be able to use int and numeric, although I wouldn't bother myself, just change your model to decimal to match the datatype mapping... https://msdn.microsoft.com/en-us/library/cc716729(v=vs.110).aspx... if you have a need to use numeric.
Also decorate your class with the Key attribute
[Table("MovieMaster")]
public class MoviesListing
{
[Key]
public int MovieId { get; set; }
public string Name { get; set; }
public string year { get; set; }
public string Image { get; set; }
public string producer { get; set; }
public string plot { get; set; }
}
You can read about using a decimal (numeric) as a key http://dotnetwindow.blogspot.co.uk/2012/06/using-decimal-as-primary-key-in-entity.html
BTW, are you using code first?

Answer 2

add property to your entity
[Table("MovieMaster")]
public class MoviesListing
{
public int Id { get; set; } // add this
public int MovieId { get; set; }
public string Name { get; set; }
public string year { get; set; }
public string Image { get; set; }
public string producer { get; set; }
public string plot { get; set; }
}
or else use this
public class MovieContext:DbContext
{
public DbSet<MoviesListing> Movies { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<MoviesListing>.HasKey(x => x.MovieId );
base.OnModelCreating(modelBuilder);
}
}