c# - Entity Framework - Remove object with foreign key, preserving parent

Question

I have have the following models:

public class Company
{
    //Primary key
    public string ID { get; set; } 

    //Foreign key
    public int? LogotypeID { get; set; }
}

and

public class Logotype
{
    //Primary key
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int? ID { get; set; }

    //Foreign key
    public string CompanyID { get; set; }
}

How do I delete the logotype from the Company table, without removing the company row?

Using:
http://msdn.microsoft.com/en-us/library/system.data.entity.dbset.remove(v=vs.113).aspx DbSet.Remove(Logotype) thows the following exception:

{"The DELETE statement conflicted with the REFERENCE constraint "FK_dbo.Companies_dbo.Logotypes_LogotypeID". The conflict occurred in database "ShipReg", table "dbo.Companies", column 'LogotypeID'.
The statement has been terminated."}

Any ideas?

Br, Tim

Answer 1

add a virtual property in company like

public class Company
{
    //Primary key
    public string ID { get; set; } 

    //Foreign key
    public int? LogotypeID { get; set; }

    public virtual Logotype Logotype {get;set;}
}

and then

dbContext.Entry<Company>(company).State=EntityState.Modified;
dbContext.Entry<Logotype>(company.Logotype).State=EntityState.Deleted;