using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration;

namespace Northwind.Model.Mapping
{
    public class OrderDetailMap : EntityTypeConfiguration<OrderDetail>
    {
        public OrderDetailMap()
        {
            // Primary Key
            HasKey(t => new { t.OrderId, t.ProductId });

            // Properties
            Property(t => t.OrderId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);

            Property(t => t.ProductId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);

            // Table & Column Mappings
            ToTable("OrderDetails");
            Property(t => t.OrderId).HasColumnName("OrderID");
            Property(t => t.ProductId).HasColumnName("ProductID");
            Property(t => t.UnitPrice).HasColumnName("UnitPrice");
            Property(t => t.Quantity).HasColumnName("Quantity");
            Property(t => t.Discount).HasColumnName("Discount");

            // Relationships
            HasRequired(t => t.Order)
                .WithMany(t => t.OrderDetails)
                .HasForeignKey(d => d.OrderId);
            HasRequired(t => t.Product)
                .WithMany(t => t.OrderDetails)
                .HasForeignKey(d => d.ProductId);
        }
    }
}

using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration;

namespace Northwind.Model.Mapping
{
    public class OrderDetailMap : EntityTypeConfiguration<OrderDetail>
    {
        public OrderDetailMap()
        {
            // Primary Key
            HasKey(t => new { t.OrderId, t.ProductId });

            // Properties
            Property(t => t.OrderId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);

            Property(t => t.ProductId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);

            // Table & Column Mappings
            ToTable("Order Details");
            Property(t => t.OrderId).HasColumnName("OrderID");
            Property(t => t.ProductId).HasColumnName("ProductID");
            Property(t => t.UnitPrice).HasColumnName("UnitPrice");
            Property(t => t.Quantity).HasColumnName("Quantity");
            Property(t => t.Discount).HasColumnName("Discount");

            // Relationships
            HasRequired(t => t.Order)
                .WithMany(t => t.OrderDetails)
                .HasForeignKey(d => d.OrderId);
            HasRequired(t => t.Product)
                .WithMany(t => t.OrderDetails)
                .HasForeignKey(d => d.ProductId);
        }
    }
}

Change OrderDetails table name from 'OrderDetails' to 'Order Details' in the mapping.
Change OrderDetails table name from 'OrderDetails' to 'Order Details' in the mapping.
