Chapter 7: Creating and Managing Views Using PROC SQL
Correct answer: a
A PROC SQL view accesses
the most current underlying data and can be joined with tables or
other views. In addition, a PROC SQL view can
be used in SAS programs in place
of an actual SAS data file
be derived from one or more tables,
PROC SQL views, or DATA step views.
Correct answer: d
PROC SQL views are useful
because they
often save space (a view is usually
quite small compared with the data that it accesses)
prevent users from continually
submitting queries to omit unwanted columns or rows
hide complex joins or queries from
users.
In addition, PROC SQL
views
ensure that input data sets are
always current, because data is derived from tables at execution time
can be used to shield sensitive
or confidential columns from users while enabling the same users to
view other columns in the same table.
Correct answer: c
You use the CREATE VIEW
statement to create a view. The keywords CREATE VIEW are followed
by the name of the view and the keyword AS.
Correct answer: b
The DESCRIBE VIEW statement
displays the view definition in the SAS log.
Correct answer: a
A view can be used in
a PROC SQL step just as you would use an actual SAS table.
Correct answer: d
The USING clause enables
you to embed a LIBNAME statement in your view definition. The USING
clause must be the last clause in the CREATE VIEW statement.
Correct answer: d
PROC SQL views can access
data from a SAS data file, a DATA step view, a PROC SQL view, or a
relational database table.
Correct answer: d
When you are working
with PROC SQL views, it is best to
avoid using an ORDER BY clause
in a view. If you specify an ORDER BY clause, the data must be sorted
each time the view is referenced.
avoid creating views that are based
on tables whose structure might change. A view is no longer valid
when it references a nonexistent column.
specify a one-level name in the
FROM clause if the view resides in the same SAS data library as the
contributing table(s). Using a one-level name in the FROM clause prevents
you from having to change the view if you assign a different libref
to the SAS data library that contains the view and its contributing
table or tables.
Correct answer: c
You can update a PROC
SQL view provided that the view does not join or link to another table,
the view does not have a subquery, or you try to update a derived
column. You can update a view that contains a WHERE clause. The WHERE
clause can be in the UPDATE clause or in the view. You cannot update
a view that contains any other clause such as an ORDER BY or a HAVING
clause.
Correct answer: b
The DROP VIEW statement
drops a view from the specified library.