Because a view is defined by a query that references other objects (tables, materialized
views, or other views), a view depends on the referenced objects. Oracle automatically
handles the dependencies for views. For example, if you drop a base table of a view
and then create it again, Oracle determines whether the new base table is acceptable to
the existing definition of the view.

视图的依赖性
1. 由于视图的定义是一个引用了其他对象的查询,因此视图依赖于其所引用的对象
2. Oracle 会自动地处理视图的依赖性