oracle internal table
internal RDBMS table
X$ : encrypted, sysdba only, fundation of internal mechanism.
example:X$KVIT
Data dictionary(table)
%$ : for storing database structure and definition, created by
sql.bspand$ORACLE_HOME/rdbms/admin
example:OBJ$
static data dictionary(view)
more stable than DD, based on
X$%and%$.
A user have different levels of SDD.
| type | desc | example | ||
|---|---|---|---|---|
| user_% | objects that belong to user own | user_tables | ||
| all_% | objects that not belong to user but could access to | all_tables | ||
| dba_% | all table, only for sysdba role | dba_users |
dynamic performance view(view)
Including and reflect performance of system, dynamic, based on X$%
| type | desc | example | ||
|---|---|---|---|---|
| GV$% | including all instances | GV$METRIC | ||
| V$% | local instance only | V$METRIC |
order of accessing
- analyse object name
- the table and view of user own
- private synonym
- public synonym
- throw
ORA-00942(cannot find object)