Answer / santosh kumar

View is the logical representation of subset of data from
one or more table.(This is database object but depends on
the table).
there are two types of view.....
1. simple view
2. complex view
SIMPLE VIEW
note:- 1. based on one table.
2. We can perform dml in this.
3. can not contain group function.
4. can not contain group by clause.
5. dml can not be perform when the base table have
not null(primary key, not null) constraint on
any column and that is not selected in the view.

COMPLEX VIEW
note:- 1. based on one or more table.
2. We can perform dml in this always.
3. can contain group function.
4. can contain group by clause.

Answer / kiran kumar

DML operation can not perform on complex view
if the SELECT statement in a view contain in any one of the
following
1) DISTINCT operation
2) Aggregate functions
3) Group by or HAVING clause

Answer / satish asnani

Answer from Santosh Kumar is correct with slight
improvement. The simple views are actually called Updateable
Views and Complex views are called Non-Updateable Views.
Updateable means we can perform DML operations(Insert,
Update & Delete) on such views. Non-Updateable means we
cannot perform DML operations.

Answer / subbu

Yes the above is true. In simple a View is nothing but a
snapshot of original table/tables.

Answer / santosh kumar

Hi Friends,
This is Santosh Kumar, I just want to update one important
point in my answer that i missed before is
1. complex view cann't be updated always but by using
autonomous transaction in trigger we can update complex view
also........
thanks,
Santosh Kumar

Answer / satish asnani

Simple and complex views do not occupy HD space. The data
remains with the base table and views are just stored
queries which fetch data from base tables. But Materialized
Views maintain a copy of the records in their own space.
That is Materialized views as name suggests store a local
copy of the records from base tables and definitely occupy
HD space.

Answer / sunitha

View is a logical representation of subset of data.
there are simple,complex and materialized views.
View does't take any space in database.
view are used for security purpose.

Answer / udaykumar

view is a virtual memory.it doesn't contain the data but it
has a structure.
simple
complex
materialized
snapshot
force
inline
parametric

Answer / joe

View is stored query.
it have not contain data. And have not take memory.
simple,complex,materialized

Answer / karthi

view is same as table..the output of the query will be
stored in View..it is used to store the records in table
and also to retrieve it..

Is join same as left join?

0 Answers  

What is the file extension for sql database?

0 Answers  

How do I clear the screen in sql plus?

0 Answers  

Why stored procedures are faster than query?

0 Answers  

What is auto increment?

0 Answers  

What is the maximum number of triggers,can apply to a single table?

2 Answers  

how to see the create table statement of an existing table? : Sql dba

0 Answers  

What is a pl/sql block?

0 Answers  

what are the 'mysql' command line arguments? : Sql dba

0 Answers  

What language is oracle sql developer?

0 Answers  

how to check the 3rd max salary from an employee table? One of the queries used is as follows: select sal from emp a where 3=(select count(distinct(sal)) from emp b where a.sal<=b.sal). Here in the sub query "select count(distinct(sal)) from emp b where a.sal<=b.sal" or "select count(distinct(sal)) from emp b where a.sal=b.sal" should reveal the same number of rows is in't it? Can any one here please explain me how is this query working perfectly. However, there is another query to get the 3rd highest of salaries of employees that logic I can understand. Pls find the query below. "select min(salary) from emp where salary in(select distinct top 3 salary from emp order by salary desc)" Please explain me how "select sal from emp a where 3=(select count(distinct(sal)) from emp b where a.sal<=b.sal)" works source:http://www.allinterview.com/showanswers/33264.html. Thanks in advance Regards, Karthik.

4 Answers  

Can we create table in function?

0 Answers