System Tables Views Oracle PLSQL

SQL>
SQL> create table emp
  2  ( empno      NUMBER(4)    constraint E_PK primary key
  3  , ename      VARCHAR2(8)
  4  , init       VARCHAR2(5)
  5  , job        VARCHAR2(8)
  6  , mgr        NUMBER(4)
  7  , bdate      DATE
  8  , sal       NUMBER(6,2)
  9  , comm       NUMBER(6,2)
 10  , deptno     NUMBER(2)    default 10
 11  ) ;
Table created.
SQL> create synonym e for emp;
Synonym created.
SQL>
SQL> describe e
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EMPNO                                     NOT NULL NUMBER(4)
 ENAME                                              VARCHAR2(8)
 INIT                                               VARCHAR2(5)
 JOB                                                VARCHAR2(8)
 MGR                                                NUMBER(4)
 BDATE                                              DATE
 SAL                                                NUMBER(6,2)
 COMM                                               NUMBER(6,2)
 DEPTNO                                             NUMBER(2)
SQL>
SQL> select * from e;
no rows selected
SQL>
SQL> select * from cat;
TABLE_NAME      TABLE_TYPE
--------------- -----------
MYSTATS         TABLE
S               SEQUENCE
WORKING_CUSTOME TABLE
RS
EMP_HQ          VIEW
CUST_WITH_VARRA TABLE
Y_TEMP_TABLE
P1              TABLE
V               VIEW
IT              TABLE
TABLE_NAME      TABLE_TYPE
--------------- -----------
CUST_NO_KEY_TAB TABLE
LE
AVG_SAL         VIEW
DEMO            TABLE
EMPDEPT_V       VIEW
CUSTLOG         TABLE
IX              TABLE
EMP_DELTAS      TABLE
PARMS           TABLE
TABLE_NAME      TABLE_TYPE
--------------- -----------
PASSWORD_AUDIT  TABLE
WO_SEQ          SEQUENCE
DEPT_SAL        VIEW
DEPT$AUDIT      TABLE
ALL_ORACLE_ERRO VIEW
RS
INVENTORY_TBL   TABLE
INVENTORY_VIE   VIEW
TMP             TABLE
SEQ             SEQUENCE
TABLE_NAME      TABLE_TYPE
--------------- -----------
FRIENDIDSEQ     SEQUENCE
TOP_EMP         VIEW
EMP_BONUS       VIEW
SHARED          VIEW
SYSTEM_STATS    TABLE
EMP             TABLE
EMPLOYEETEMPTAB TABLE
LE
TEMP_TABLE      TABLE
TABLE_NAME      TABLE_TYPE
--------------- -----------
PHONE_LIST      VIEW
EMPTEMPTABLE    TABLE
P               TABLE
WORKING_EMPLOYE TABLE
ES
E               SYNONYM
WORKING_EMPS    TABLE
MYTABLE1        TABLE
40 rows selected.
SQL>
SQL> select synonym_name, table_owner, table_name
  2  from   user_synonyms;
SYNONYM_NAME                   TABLE_OWNER                    TABLE_NAME
------------------------------ ------------------------------ ---------------
E                              RNTSOFT                         EMP
SQL>
SQL> drop synonym e;
Synonym dropped.
SQL>
SQL> drop table emp;
Table dropped.