public void FromClauseUsingInstance()
        {
            OrderCollection collection = new OrderCollection();

            collection.es.Connection.Name = "ForeignKeyTest";

            // Select an arbitrary number of rows from
            // any starting row.
            int startRow     = 4;
            int numberOfRows = 7;

            // OrderItem SubQuery 1
            // Get all rows through start + number, ascending
            OrderItemQuery oisq = new OrderItemQuery("ois");

            oisq.es.Top = startRow + numberOfRows - 1;
            oisq.Select(oisq.OrderID, oisq.ProductID, oisq.Quantity);
            oisq.OrderBy(oisq.OrderID.Ascending,
                         oisq.ProductID.Ascending);

            // OrderItem SubQuery 2
            // Get just the number of rows, descending
            OrderItemQuery oisq2 = new OrderItemQuery("ois2");

            oisq2.es.Top = numberOfRows;
            oisq2.From(oisq).As("sub1");

            switch (collection.es.Connection.ProviderSignature.DataProviderName)
            {
            //case "EntitySpaces.SqlServerCeProvider":
            //    Assert.Ignore("Not supported.");
            //    break;
            case "EntitySpaces.NpgsqlProvider":
            case "EntitySpaces.Npgsql2Provider":
                oisq2.OrderBy("<sub1.\"OrderID\">", esOrderByDirection.Descending);
                oisq2.OrderBy("<sub1.\"ProductID\">", esOrderByDirection.Descending);
                break;

            case "EntitySpaces.OracleClientProvider":
                Assert.Ignore("Not supported.");
                break;

            default:
                oisq2.OrderBy("<sub1.OrderID>", esOrderByDirection.Descending);
                oisq2.OrderBy("<sub1.ProductID>", esOrderByDirection.Descending);
                break;
            }

            // Put it back in ascending order
            OrderQuery oq = new OrderQuery("o");

            oq.From(oisq2).As("sub2");

            switch (collection.es.Connection.ProviderSignature.DataProviderName)
            {
            case "EntitySpaces.NpgsqlProvider":
            case "EntitySpaces.Npgsql2Provider":
                oq.OrderBy("<sub2.\"OrderID\">", esOrderByDirection.Ascending);
                oq.OrderBy("<sub2.\"ProductID\">", esOrderByDirection.Ascending);
                break;

            default:
                oq.OrderBy("<sub2.OrderID>", esOrderByDirection.Ascending);
                oq.OrderBy("<sub2.ProductID>", esOrderByDirection.Ascending);
                break;
            }

            Assert.IsTrue(collection.Load(oq));
            Assert.AreEqual(7, collection.Count);
            Assert.AreEqual(10, collection[0].GetColumn("Quantity"));
        }