The Complete Guide to Oracle Application R12 VIEWS

 Database Objects in Oracle :

1. TABLE:  Used to store information & allows manipulation, retrieval & share of information.

 ( user_tables, user_tab_columns ,TAB )

2. VIEWS & SYNONYMS: Used to manipulate, retrieve &  share information. They will not hold data.

 ( user_views, user_synonyms, CAT )

3. SEQUENCES: Used to generate the numbers automatically. 

( user_sequences )

4. INDEX & CLUSTER: Used to improve the performance of Oracle while retrieving or manipulating data.

 ( user_indexes , user_clusters )

Views: 

 It is a stored select statement.

 It is a virtual or Logical component.

 It allows Desc, DML, and Select on it.

 It will not hold data.

 It is stored permanently in the "User_views" system table.

 It can be shared with other users.

 DML on view are reflected in Table and DML on   Table are reflected in the view.

 * It is used to share "Selected Rows and Columns"   with other users. It is used for reporting purposes.

 *It will Improve performance while manipulating or retrieving data from the Views.