Retrieve Data Through Views

When you retrieve data through a view, SAP ASE verifies that all the database objects referenced anywhere in the statement exist and that they are valid in the context of the statement. If the checks are successful, SAP ASE combines the statement with the stored definition of the view and translates it into a query on the view’s underlying tables.

This process is called view resolution.

Consider the following view definition statement and a query against it:

create view hiprice 
as select * 
from titles 
where price > $15 
and advance > $5000 
select title, type 
from hiprice 
where type = "popular_comp" 

Internally, SAP ASE combines the query of hiprice with its definition, converting the query to:

select title, type 
from titles 
where price > $15 
and advance > $5000 
and type = "popular_comp" 

In general, you can query any view in any way just as if it were a real table. You can use joins, group by clauses, subqueries, and other query techniques on views, in any combination. However, if the view is defined with an outer join or aggregate function, you may get unexpected results when you query the view.

• View Resolution
  When you define a view, SAP ASE verifies that all the tables or views listed in the from clause exist. Similar checks are performed when you query through the view.
• Redefine Views
  You can redefine a view without redefining other views that depend on it, unless the redefinition makes it impossible for SAP ASE to translate the dependent view.
• Rename Views
  You can rename a view using sp_rename.
• Alter or Drop Underlying Objects
  You can change the name of a view’s underlying objects. For example, if a view references a table that is named new_sales, and you rename that table to old_sales, the view works on the renamed table.