System Tables Data Dictionary Oracle PLSQL Tutorial

SQL>
SQL> desc all_tables;
 Name                             Null?    Type
 OWNER                            NOT NULL VARCHAR2(30)
 TABLE_NAME                       NOT NULL VARCHAR2(30)
 TABLESPACE_NAME                           VARCHAR2(30)
 CLUSTER_NAME                              VARCHAR2(30)
 IOT_NAME                                  VARCHAR2(30)
 STATUS                                    VARCHAR2(8)
 PCT_FREE                                  NUMBER
 PCT_USED                                  NUMBER
 INI_TRANS                                 NUMBER
 MAX_TRANS                                 NUMBER
 INITIAL_EXTENT                            NUMBER
 NEXT_EXTENT                               NUMBER
 MIN_EXTENTS                               NUMBER
 MAX_EXTENTS                               NUMBER
 PCT_INCREASE                              NUMBER
 FREELISTS                                 NUMBER
 FREELIST_GROUPS                           NUMBER
 LOGGING                                   VARCHAR2(3)
 BACKED_UP                                 VARCHAR2(1)
 NUM_ROWS                                  NUMBER
 BLOCKS                                    NUMBER
 EMPTY_BLOCKS                              NUMBER
 AVG_SPACE                                 NUMBER
 CHAIN_CNT                                 NUMBER
 AVG_ROW_LEN                               NUMBER
 AVG_SPACE_FREELIST_BLOCKS                 NUMBER
 NUM_FREELIST_BLOCKS                       NUMBER
 DEGREE                                    VARCHAR2(10)
 INSTANCES                                 VARCHAR2(10)
 CACHE                                     VARCHAR2(5)
 TABLE_LOCK                                VARCHAR2(8)
 SAMPLE_SIZE                               NUMBER
 LAST_ANALYZED                             DATE
 PARTITIONED                               VARCHAR2(3)
 IOT_TYPE                                  VARCHAR2(12)
 TEMPORARY                                 VARCHAR2(1)
 SECONDARY                                 VARCHAR2(1)
 NESTED                                    VARCHAR2(3)
 BUFFER_POOL                               VARCHAR2(7)
 ROW_MOVEMENT                              VARCHAR2(8)
 GLOBAL_STATS                              VARCHAR2(3)
 USER_STATS                                VARCHAR2(3)
 DURATION                                  VARCHAR2(15)
 SKIP_CORRUPT                              VARCHAR2(8)
 MONITORING                                VARCHAR2(3)
 CLUSTER_OWNER                             VARCHAR2(30)
 DEPENDENCIES                              VARCHAR2(8)
 COMPRESSION                               VARCHAR2(8)
 DROPPED                                   VARCHAR2(3)
SQL>
SQL> --select * from all_tables;