The Three Sets of Data Dictionary Views: USER_,ALL_,DBA_*

Oracle doesn’t allow you to access the internal data dictionary tables directly.
It creates views on the base dictionary tables and creates public synonyms for these views so users can access them.

There are three sets of data dictionary views—USER, ALL, and DBA—with each set of views pertaining to a similar item containing similar columns.


The views in each category are prefixed by the keywords USER, ALL, or DBA.


Each of these sets of views shows only the information the user is granted privileges
to access, as follows:

*** USER: The USER views show a user only those objects that the user owns. These views are useful to users, especially developers, for viewing the owner’s objects, grants, and so on.


*** ALL: The ALL views show you information about objects for which you have been granted privileges. The views with the prefix ALL include information on the user’s objects, and all other objects on which privileges have been granted, directly or through a role.


*** DBA: The DBA views are the most powerful in their range. Users who have been assigned the DBA role can access information about any object or any user in the database.

The DBAprefixed dictionary views are the ones you use to monitor and administer the database.