First, ASP.NET MVC code: Multiplicity is not acceptable in relationship roles.

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First, ASP.NET MVC code: Multiplicity is not acceptable in relationship roles.

asp.net c# entity-framework

Question

I am in a straightforward marriage. Two Pages are connected to a campaign. One campaign may only have one link to a page. But I keep encountering this mistake:

System.Data.Edm.EdmAssociationEnd: : Multiplicity is not valid in Role 'Page_Campaign_Source' in relationship 'Page_Campaign'. Because the Dependent Role properties are not the key properties, the upper bound of the multiplicity of the Dependent Role must be '*'.

While comparing it to my code, I looked through numerous tutorials and sample codes, but I couldn't locate any errors.

 public class Campaign
    {
        [Key()]
        public int Campaignid { get; set; }
        public string Name { get; set; }

        public virtual Page LandingPage { get; set; }
        public virtual RedeemPage RedeemPage { get; set; }
    }


public class Page
{
    [Key()]
    public int PageContentId { get; set; }
    public string Logo { get; set; }
    public string Css { get; set; }

    [ForeignKey("Campaign")]
    public int campaignID { get; set; }
    public virtual Campaign Campaign { get; set; }
}

Edit

I utilized the Fluent API in instead of using Eranga's suggestion, but now I'm getting:

An error occurred while saving entities that do not expose foreign key properties for their relationships

Reinard

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Eranga · Accepted Answer · 3/27/2012 11:42:46 AM

In this circumstance, the Data Annotations Mapping is unclear. Configure Fluent via the API. Use fluent API as follows and remove the data annotations for navigational property mapping.

class MyContext : DbContext
{

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Campaign>().HasRequired(x => x.LandingPage)
           .WithMany();

        modelBuilder.Entity<Page>().HasRequired(x => x.Campaign)
           .WithMany()
           .HasForeignKey(x => x.campaignID); 

      base.OnModelCreating(modelBuilder);
    }
}

Edit

the issue after settingWillCascadeOnDelete(false) Is both that?Campaign and Page has automatically increasing PKs and a 1-to-1 mapping. As a result, in order to save one record, it requires both the ID of the first row and the ID of the second row that was just put.

You may either make 1 FK nullable and call to or alter the PK to be a GUID.SaveChanges two times.

The connection is now nullable.

    modelBuilder.Entity<Campaign>().HasOptional(x => x.LandingPage)
       .WithMany();


using(var scope = new TransactionScope())
{

       context.Campaigns.Add(campaign);
       context.SaveChanges();

       page.CampaignId = campaign.CampaignId;
       context.Pagess.Add(page);
       context.SaveChanges();

       scope.Complete();
}

First, ASP.NET MVC code: Multiplicity is not acceptable in relationship roles.

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