The Extended objects                               
Up to now, we have been considering primitive filtering object forms, in which only one of filtering object had a precisely
defined number/ condition. At this point, we shall take into consideration the objects with the indefinite number of conditions.
We shall have a look at the following example:

SELECT ;
                                    order. number_invoice ;
                                    order. order_date ;
                                    order.value_invoice ;
                                    order. payment ;
                                    customer. company_name ;
                        FROM order, customer ;
                         WHERE ( BETWEEN(order.value_invoice = 200,220)     .OR. ;
                                        BETWEEN(order.value_invoice = 300,330)      .OR. ;
                                        BETWEEN( order.value_invoice = 660,662)     .OR. ;
                                        BETWEEN(order.value_invoice = 1020,1270)  .OR. ;
                                        order.value_invoice => 1900)

One field has more different conditions. There are five different conditions in our example. Theoretically, the number of them may be indefinite, but practically every producer of SQL limits the number of values.
Let’s go back to our scetches! Any contemplation by means of scetches brings to very quick solutions. At the same time, it assists the user in his contemplation of potential object making in due course. Some actions must be performed on the object.
What are we supposed to have:
            1)       Main switch for  “On/Off”
            2)       Operator “NOT”
            3)       Filtering object name
            4)       Selection of the main operator “AND/OR”

In order to have our operator in accordance with the requests, we need to add some room for the list members.

In order to add/delete the list members, we are to add the switchers for such actions.