In another parallel with functions, database users can manipulate nested views, thus one view can aggregate data from other views.
Without the use of views, the normalization of databases above second normal form would become much more difficult.
Stacked canvases obscure some part of the underlying content canvas, and often are shown and hidden programmatically.
You can display more than one stacked canvas in a window at the same time This sample show how you can base a block on a view that aggregate the columns of several tables (in this case, DEPT and EMP) and when you can insert, update and delete from the target tables from this view.
If you want a join view to be updatable, then all of the following conditions must be true: Generally, you should not rely on being able to perform an insert to a view unless you have specifically written an INSTEAD OF trigger for it.