Complex Views in SQL Server:-
Views are based on more than one table and also based on
- Group by clause
- Having clause
- Distinct clause
- Aggregate function
- Expression.
Then view is said to be “complex view”.
Difference between simple view and complex view in sql:
Simple view
- It is updatable {updatable means allow DML operations}
complex view
- but complex views are not updatable.
Example :
Create view v5 as select e.empno, e.ename, e.sal, d.deptno ,d.dname from e.emp , d.dept.
- Query fired on view takes more times than query fired on base table.
Views degrades performance
- Select * from information_schema.views ( This maintains information about the views created by user)