MVC 4 and EF6 database first: issue with mapping

Question

I am following along Pro ASP.NET MVC 4 by Adam Freeman on VS 2010 (I downloaded the MVC 4 template online). I have worked with the .edmx file before, but in Chapter 7 he does not do this. I setup a basic connection string with SQL Server in my web.config file within my WebUI project where my controllers and views are located. Also, I listed my Domain classes within my Domain project below. The problem comes when I run the application. The application is not recognizing my table in my database (dbo.Request) and instead is creating a table based on my class name in the Entities namespace (so it creates a CustRequest table) and it also creates a _Migration_History table. To prevent this I add the Data Annotation above my class [Table("MyTableName")]. I could not figure out why I had to add this Data Annotation. Also, EF made me add a [Key] above my primary key, which i can understand because i do not have an ID property, but in the book he did not do this. I was wondering if I was missing something obvious as I am pretty new to MVC. Any help would be appreciated. I am working with EF 6. Thank you.

    namespace Requestor.Domain.Entities
    {
        [Table("Request")]
        public class CustRequest
        {
            [Key]
            public int RequestId { get; set; }
            public string RequestByUserCd { get; set; }
            public DateTime RequestDateTime { get; set; }
            public DateTime DueDate { get; set; }
        }
    }

    namespace Requestor.Domain.Abstract
    {
        public interface ICustRequestRepository
        {
            IQueryable<CustRequest> Request { get; }
        }
    }

    namespace ITRequestHub.Domain.Concrete
    {
        public class EFDbContext : DbContext
        {
            public DbSet<CustRequest> Request { get; set; }
        }
    }


    namespace ITRequestHub.Domain.Concrete
    {
        public class EFCustRequestRepository : ICustRequestRepository
        {
            private EFDbContext context = new EFDbContext(); //retrieves the data

            public IQueryable<CustRequest> Request
            {
                get { return context.Request; }
            }
        }
    }

bedane · Accepted Answer · 2014-01-20 12:50:04Z

1

Consider trying again with EF5 if you can, I experienced similar issues when trying to make EF6 work with MVC4 (I couldn' make scaffolding work either).

Or go all the way up to the latest versions for everything and try MVC5 with EF6 (this seems to work fine)

answered Jan 20, 2014 at 12:50

bedane

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ProxyTech · Accepted Answer · 2014-01-20 13:04:43Z

0

You've run into the wonderful and sometimes frustrating part of EF, its conventions. Wonderful when you're aware of the conventions as they simplify life, but frustrating when you feel that the framework is performing tasks without your explicit permission.

Firstly, additional information on EF6 conventions can be found here: http://msdn.microsoft.com/en-gb/data/jj679962.aspx

On your first point, as far as I'm aware, EF takes the name of your entity as the name of the table it will create in your DB. As you've discovered, you do have control over this via the "Table" attribute, but you can also control it's desire to want to pluralize your entity names when creating tables by means convention removal within your DbContext

modelBuilder.Conventions.Remove<PluralizingTableNameConvention>()

On your second point, I cannot imagine that you would require a "Key" attribute attached to your "RequestId" field. The convention here is that if the field name contains a suffix of ID (case-insensitive), then EF will automatically include it as a primary key and if the type of the field is either an Int or a Guid it will be automatically set as an auto-seed identity column.

answered Jan 20, 2014 at 13:04

ProxyTech

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3 Comments

jmzagorski Over a year ago

so, in the book, he mentions that DbSet<> is where the mapping happens. The name of the property is the table and the type of DbSet is the class to model. Has this changed with EF6 (I am reading over the EF article now)

ProxyTech Over a year ago

@JayMichael I don't think this was ever the case that the name of the DbSet property mapped to the name of the table within your DB. It's always been mapped to the name of the entity class. See here: msdn.microsoft.com/en-gb/data/jj591583#TableColumn

jmzagorski Over a year ago

that seemed to do this trick. I added

protected override void OnModelCreating(DbModelBuilder modelBuilder){         modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();  Database.SetInitializer<EFDbContext>(null);}

I was able to remove the DataAnnotations. That is interesting what you said, maybe I read the passage in the book incorrectly.

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