Talk about views
Answers were Sorted based on User's Feedback
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.
Is This Answer Correct ? | 20 Yes | 5 No |
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
Is This Answer Correct ? | 6 Yes | 1 No |
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.
Is This Answer Correct ? | 5 Yes | 1 No |
Answer / subbu
Yes the above is true. In simple a View is nothing but a
snapshot of original table/tables.
Is This Answer Correct ? | 5 Yes | 4 No |
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
Is This Answer Correct ? | 1 Yes | 0 No |
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.
Is This Answer Correct ? | 1 Yes | 0 No |
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.
Is This Answer Correct ? | 0 Yes | 0 No |
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
Is This Answer Correct ? | 1 Yes | 2 No |
Answer / joe
View is stored query.
it have not contain data. And have not take memory.
simple,complex,materialized
Is This Answer Correct ? | 0 Yes | 3 No |
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 This Answer Correct ? | 0 Yes | 9 No |
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