access all_mview or user_mviews from app code I need to access the user_mviews or all_mviews table to get meta information about materialized view in my app. Which grants are necessary to read the user_mviews table?
by default all users can read the user_mviews and all_mviews views since the SELECT right is granted to public:

SQL&gt; SELECT grantee, privilege, table_name
  2    FROM dba_tab_privs
  3   WHERE table_name IN ('USER_MVIEWS', 'ALL_MVIEWS');

GRANTEE  PRIVILEGE  TABLE_NAME
-------- ---------- ------------
PUBLIC   SELECT     USER_MVIEWS
PUBLIC   SELECT     ALL_MVIEWS


If for some reason this grant has been removed, you would need to regrant the rights to either public or a specific user (with a DBA account):

GRANT SELECT ON user_mviews TO &lt;user&gt;;




Edit: By definition, USER_MVIEWS describes materialized views owned by the current user while ALL_MVIEWS describes the materialized views accessible to the current user (the user needs to be granted SELECT on the mview either directly or through a role).