EF Code First "Invalid column name 'Discriminator'" but no inheritance

user_603637 0
Viewed 123371

I have a table in my database called SEntries (see below the CREATE TABLE statement). It has a primary key, a couple of foreign keys and nothing special about it. I have many tables in my database similar to that one, but for some reason, this table ended up with a "Discriminator" column on the EF Proxy Class.

This is how the class is declared in C#:

public class SEntry
{
    public long SEntryId { get; set; }

    public long OriginatorId { get; set; }
    public DateTime DatePosted { get; set; }
    public string Message { get; set; }
    public byte DataEntrySource { get; set; }
    public string SourceLink { get; set; }
    public int SourceAppId { get; set; }
    public int? LocationId { get; set; }
    public long? ActivityId { get; set; }
    public short OriginatorObjectTypeId { get; set; }
}

public class EMData : DbContext
{
    public DbSet<SEntry> SEntries { get; set; }
            ...
    }

When I try to add a new row to that table, I get the error:

System.Data.SqlClient.SqlException: Invalid column name 'Discriminator'.

This problem only occurs if you are inheriting your C# class from another class, but SEntry is not inheriting from anything (as you can see above).

In addition to that, once I get the tool-tip on the debugger when I mouse over the EMData instance for the SEntries property, it displays:

base {System.Data.Entity.Infrastructure.DbQuery<EM.SEntry>} = {SELECT 
[Extent1].[Discriminator] AS [Discriminator], 
[Extent1].[SEntryId] AS [SEntryId], 
[Extent1].[OriginatorId] AS [OriginatorId], 
[Extent1].[DatePosted] AS [DatePosted], 
[Extent1].[Message] AS [Message], 
[Extent1].[DataEntrySource] AS [DataE...

Any suggestions or ideas where to get to the bottom of this issue? I tried renaming the table, the primary key and a few other things, but nothing works.

SQL-Table:

CREATE TABLE [dbo].[SEntries](
[SEntryId] [bigint] IDENTITY(1125899906842624,1) NOT NULL,
[OriginatorId] [bigint] NOT NULL,
[DatePosted] [datetime] NOT NULL,
[Message] [nvarchar](500) NOT NULL,
[DataEntrySource] [tinyint] NOT NULL,
[SourceLink] [nvarchar](100) NULL,
[SourceAppId] [int] NOT NULL,
[LocationId] [int] NULL,
[ActivityId] [bigint] NULL,
[OriginatorObjectTypeId] [smallint] NOT NULL,
CONSTRAINT [PK_SEntries] PRIMARY KEY CLUSTERED 
(
[SEntryId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF,       ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[SEntries]  WITH CHECK ADD  CONSTRAINT [FK_SEntries_ObjectTypes] FOREIGN KEY([OriginatorObjectTypeId])
REFERENCES [dbo].[ObjectTypes] ([ObjectTypeId])
GO

ALTER TABLE [dbo].[SEntries] CHECK CONSTRAINT [FK_SEntries_ObjectTypes]
GO

ALTER TABLE [dbo].[SEntries]  WITH CHECK ADD  CONSTRAINT [FK_SEntries_SourceApps] FOREIGN KEY([SourceAppId])
REFERENCES [dbo].[SourceApps] ([SourceAppId])
GO

ALTER TABLE [dbo].[SEntries] CHECK CONSTRAINT [FK_SEntries_SourceApps]
GO
ef-code-first entity-framework
8 Answers

I had a similar problem, not exactly the same conditions and then i saw this post. Hope it helps someone. Apparently i was using one of my EF entity models a base class for a type that was not specified as a db set in my dbcontext. To fix this issue i had to create a base class that had all the properties common to the two types and inherit from the new base class among the two types.

Example:

//Bad Flow
    //class defined in dbcontext as a dbset
    public class Customer{ 
       public int Id {get; set;}
       public string Name {get; set;}
    }

    //class not defined in dbcontext as a dbset
    public class DuplicateCustomer:Customer{ 
       public object DuplicateId {get; set;}
    }


    //Good/Correct flow*
    //Common base class
    public class CustomerBase{ 
       public int Id {get; set;}
       public string Name {get; set;}
    }

    //entity model referenced in dbcontext as a dbset
    public class Customer: CustomerBase{

    }

    //entity model not referenced in dbcontext as a dbset
    public class DuplicateCustomer:CustomerBase{

       public object DuplicateId {get; set;}

    }
user_87054220

Old Q, but for posterity...it also also happens (.NET Core 2.1) if you have a self-referencing navigation property ("Parent" or "Children" of the same type) but the Id property name isn't what EF expects. That is, I had an "Id" property on my class called WorkflowBase, and it had an array of related child steps, which were also of type WorkflowBase, and it kept trying to associate them with a non-existent "WorkflowBaseId" (the name i suppose it prefers as a natural/conventional default). I had to explicitly configure it using HasMany(), WithOne(), and HasConstraintName() to tell it how to traverse. But I spent a few hours thinking the problem was in 'locally' mapping the object's primary key, which i attempted to fix a bunch of different ways but which was probably always working.

user_24037440
Related