Data Analyst and Technical Consultant

Database Fundamentals: SQL Views

Database views are searchable objects in a relational database defined by a query. The view doesn’t store data but you can query a view like you can a table.

Advantages of database view

  • Through a database view, you only have to use simple SQL statements instead of complex ones with many joins.
  • A view helps limit data access to specific users. You may not want a subset of sensitive data that can be queried by all users.
  • Views take very little space to store as they do not store actual data.

 

Disadvantages of database view

  • Querying data from a database view can be slow especially if the view is created based on other views.
  • You create a view based on underlying tables of the database. Whenever you change the structure of these tables that view associated with, you have to change the view as well.

 


Creating a view

create view
view_name as
select
column1, column2, ...
from
table_name
where condition;

 

Replacing a view

create or replace view
view_name as
select
column1, column2, ...
from
table_name
where condition;

 

Dropping a view

drop view
view_name;