A view reference is a link between a parent table or view and a child table or view, which defines the joins between the parent and child columns. View references are not generated to the database
If you create a new view from existing views, the joins defined on these views influence the WHERE statement in the SQL query of the new view.
In this example, French_Store is a view of the Store
table with a view reference defining a join between Store_ID in the table and
STORE_STORE_ID in the view. Customer_Orders is a
view of the Orders table with a view reference defining a join between
Order_No in the table and ORDER_ORDER_N in the view:
You can create a view reference between the two views to define a join between
Customer_Order.ORDER_ORDER_STORE and
French_Store.STORE_STORE_ID:
If you were then to
create a view from the French_Store and Customer_Order
views, the SELECT order of the new view will take into account the join
defined between the views to retrieve only those orders sent to French stores.
