Oracle Data Dictionary (Cont.)

Data Dictionary Views (Cont.)
ALL_
Rows in the ALL views include rows of the USER views and all information about objects that are accessible to the current user. The structure of these views is similar to the structure of the USER views.

View Description
ALL_CATALOG Owner, name and type of all accessible tables, views, and synonyms
ALL_TABLES Owner and name of all accessible tables
ALL_OBJECTS Owner, type, and name of accessible database objects
ALL_TRIGGERS Information about all triggers
ALL_USERS Information about all users
ALL_VIEWS Information about all views

For example, to list the names of all accessible tables: 
   SQL> SELECT table_name FROM all_tables; 

   TABLE_NAME
   ------------------------
   ...
DBA_
It encompasses information about all database objects, regardless of the owner. Only users with DBA privileges can access these views.

View Description
DBA_TABLES Tables of all users in the database
DBA_CATALOG Tables, views, and synonyms defined in the database
DBA_OBJECTS Objects of all users
DBA_DATA_FILES Information about data files
DBA_USERS Information about all users known in the database