Answer Posted / subhajit guha
View in sql called the virtual table.Physically it has no
existance, so that it don't occupy the space.It retrives
the data from original table at runtime.
Views are stored in ORACLE system catalog.
Basically, in realtime environment views are used to
protect the main table for operation.Besides for security
purpose view must be used.i.e. one user can hide the main
tale from other user for creating view.
On basic of creation of view, it is divied into two pars....
1. Simple view: In that case columns for same table(single
table) are fetched for creating a view.
Syntax: SQL>create view <view_name> as select <column
name1.column name2....> from table where <condition>;
2. Complex view: Columns are fetched from different tables
on basis of operation would perform.Generally for join
operation it is used.
Syntax: SQL>create view <view_name> as select <col1..coln
from table 1>,<col 1..col n for table 2>....< .. for table
n> from table 1,..,table n where <condition>;
On basis of operations on view ... it is divided inti two
parts:
1. Read only view, 2. Updatable view
** incase of updatable view insertion,deletion and updation
can be done...... aggregation,rowid,rownum and any group
function cann't be performed.
** incase of read only view, only view canbe read, no DML
operations cann't be perfomed.
to drop a view ..... we use:
SQL>drop view <view_name>;
| Is This Answer Correct ? | 7 Yes | 0 No |
Post New Answer View All Answers
How do I limit the number of rows returned by an oracle query after ordering?
What is raw datatype?
what is insert all statement in sql
What is a lookup table in oracle?
How to turn on or off recycle bin for the instance?
How we can able to import our own template (users designed MS-Word templates) which has many tabular columns; need to pass some values generate by Oracle-reports9i? Actually need to import more than 400 MS-Word templates into Oracle Reports-9i to minimize layout design in Reports.
What are the different types of partitions in oracle?
What are the components of logical database structure in oracle database?
What is a view and how is it different from a table?
How to add a new column to an existing table in oracle?
What is the difference between view and materialized view in Oracle?
How to loop through data rows in the implicit cursor?
How to get a list of all background sessions in the database?
How to use "if" statements on multiple conditions?
Explain about the analyze command in oracle?
