Brand.cs

public class Brand : IBrand
{  
    public int Id { get; set; }
    public string Name { get; set; }
    public int? ParentBrandId { get; set; }
}

Brand.sql

CREATE TABLE [dbo].[tbBrand](
  [idBrand] [smallint] IDENTITY(1,1) NOT NULL,
	[braName] [varchar](100) NOT NULL,
	[idParentBrand] [smallint] NULL,
 CONSTRAINT [PK__tbBrand__E353A48E005FFE8A] PRIMARY KEY CLUSTERED 
(
	[idBrand] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

ALTER TABLE [dbo].[tbBrand]  WITH NOCHECK ADD  CONSTRAINT [FK_tbBrand_tbBrand] FOREIGN KEY([idParentBrand])
REFERENCES [dbo].[tbBrand] ([idBrand])

BrandPetaPoco.cs

using PetaPoco;

[TableName("dbo.tbBrand")]
[PrimaryKey("idBrand")]
public class Brand : IBrand
{  
    [Column("idBrand")]
    public int Id { get; private set; }
    [Column("braName")]
    public string Name { get; set; }
    [Column("idParentBrand")]
    public int? ParentBrandId { get; set; }
}

BrandRepository.cs

public class BrandRepository : PetaPocoRepositoryBase, IBrandRepository
{
    public IBrand GetById(string campaignId, int id)
    {
        //Db = Petapoco.Database
        return (IBrand)Db.FirstOrDefault<BrandPetaPoco>( id );
    }
}

IBrand.cs

public interface IBrand
{  
    int Id { get; set; }
    string Name { get; set; }
    int? ParentBrandId { get; set; }
}