FND_VIEWS , ALL_TABLES , BEN_ALL_TAB_COLUMNS

Table Or View:  Table

Important columns: 

View_Name , View_ID ,Application_ID

Description: 

FND_VIEWS contains the list of all the views present in the database.
Select * From apps. FND_VIEWS, ‘ll show all the tables in database

ALL_TABLES

Basics

Table Or View: Table

Important columns: Table_name

Description: 

All_tables contains the list of all the tables present in the database.
Select *  From all_tables , ‘ll show all the tables in database

BEN_ALL_TAB_COLUMNS

Table Or View: View

Important columns: Table_name ,Column_name , Data_type

Description: This view contians information about all the tables and columns