Disadvantages of Views

Disadvantages
Although views provide many significant benefits, there are also some disadvantages with
SQL views.
Update restriction
In Section 6.4.5 we showed that, in some cases, a view cannot be updated.
Structure restriction
The structure of a view is determined at the time of its creation. If the defining query
was of the form SELECT * FROM . . . , then the * refers to the columns of the base table
present when the view is created. If columns are subsequently added to the base table, then
these columns will not appear in the view, unless the view is dropped and recreated.
Performance
There is a performance penalty to be paid when using a view. In some cases, this will be
negligible; in other cases, it may be more problematic. For example, a view defined by a
complex, multi-table query may take a long time to process as the view resolution must
join the tables together every time the view is accessed. View resolution requires additional
computer resources. In the next section, we briefly discuss an alternative approach to
maintaining views that attempts to overcome this disadvantage.