• ⬅ PL - SQL
• Lec 17
• Views
• Use Cases
• Syntax and examples
• Assignment-1 →
• Assignment-2 →

Lec - 17

Views

• Virtual tables for sqls(if not specified, won't be stored physically )
• Are created from our base tables
• Whatever we add in base table, is available in view and vice-versa
  • Cannot add record from view to base if the view does not contain some field which has not null constraint

Use cases

1. Providing restricted access to some users
2. For better performance of join queries which are executed frequently
   • works like cache, once we join some tables we can store it usign a view and the access again

Syntax and examples

create view <view_name> as <select_query>;

• creating a read only view

create view <view_name> as <select_query> with read only;

• creating a view check option
• we create view with some where condition
• and if we try to add data which violated where condition, then it will through some error

create view <view_name> as <select_query with where> with check option;

• when we create a view using a join query, we cannot add data using view