The Oracle Data Dictionary contains information about data base objects, users and events.  You can access this information through these views of the data dictionary.  For details on how these views/tables are structured and how they are used, please refer to the Oracle Data Base Reference documentation.

||View             ||Description
|[USER_ROLE_PRIVS]  |Roles granted to the user.
|[USER_TABLES] aka TABS|Description of the user's own tables.
|[USER_TAB_COLUMNS] aka COLS|Columns of user's tables, views and clusters.
|[USER_TAB_PRIVS]   |Grants on objects for which the user is the owner, grantor or grantee
|[USER_VIEWS]       |Test of views owned by the user. 
|[USER_TRIGGERS]    |Descriptions of the user's triggers
|[USER_OBJECTS] aka OBJ|Objects owned by the user
|[USER_INDEXES] aka IND|Description of the user's own indexes
|[USER_IND_COLUMNS] |Columns of the user's indexes or on user's tables
|[USER_SEQUENCES]   |Description of the user's own sequences
|[USER_SOURCE]      | The text source of the stored objects