Interfaces + IQueryable = Love

sample.cs

public interface IWithRating
{
    int Rating { get; set; }
}
public class Product:IWithRating
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int Rating { get; set; }
}

public class StoreContext : DbContext
{
    public DbSet<Product> Products { get; set; }
}

public static class RatingExtensions
{
    public static IQueryable<T> NiceRating<T>(this IQueryable<T> q) where T : class, IWithRating
    {
        return q.Where(x => x.Rating > 50);
    }
}

class Program
{
        
    static void Main(string[] args)
    {
        using (var ctx = new StoreContext())
        {
            ctx.Database.Log = Console.WriteLine;

            var q = from p in ctx.Products.NiceRating()
                    where p.Name.StartsWith("a")
                    select new { p.Id, p.Name };
            q.ToArray();
        }
    }
}