cannot perform override in class inheritance in ADO .NET Entity Model edmx-CodePudding

I have to build a .net web application accessing tables of an existing db.

The db uses different tables for different companies: customers in company "ACorp" are stored in table "ACorpCustomers", those in company "B" are stored in table "BCorpCustomers".

Using ADO .NET Entity Model, I created a different Db Context for each Company:

public partial class ACorpContext : DbContext
    {
        public ACorpContext()
            : base("name=ACorpContext")
        {
        }
    
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            throw new UnintentionalCodeFirstException();
        }
    
        public virtual DbSet<ACorpCustomer> ACorpCustomers { get; set; }
    }
}

The edmx generates also the class

public partial class ACorpCustomer
{
    public string Name { get; set; }
    public string Phone { get; set; }
}

I created a parent class Customer to be used in the application, with the same properties:

public class ACorpCustomer
{
    public virtual string Name { get; set; }
    public virtual string Phone { get; set; }
}

I havent't found a way to let the specific entity ACorpCustomers inherit from the parent Customer; the edmx returns the inheritance error, but there is no way to override the properties.

CodePudding user response：

Your definition

public partial class ACorpCustomer

has nothing to do with inheritance. partial is a .NET moderator that signifies that your class definition is a part of the bigger definition. For example if you have your class split between 2 code files. .Net "puts" them together and you endup with one type

Here what you seem need to do is


public abstract class Customer
{
    public string Name { get; set; }
    public string Phone { get; set; }
}

public class ACorpCustomer : Customer
{
    // may be, some unique properties here
}

public class BCorpCustomer : Customer
{
    // may be, some unique properties here
}

The properties Name and Phone don't even need to be virtual. Looking back into your title, there is nothing that you need to override. Nothing that I see..

CodePudding user response：

This is trivial in Code-First, which you can (and should) use with an existing database. Just map the single Customer entity to the correct table for each DbContext:

    public partial class ACorpContext : MyBaseDbContext
    {
    
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Customer>().ToTable("ACorpContext");
        }
    
        public virtual DbSet<Customer> Customers{ get; set; }
    }