如何编程得到一个oracle数据表的所有字段名和类型及长度？

Question

利用colSQL> desc col
 名称                                      空?      类型
 ----------------------------------------- -------- ---------------
 TNAME                                     NOT NULL VARCHAR2(30)
 COLNO                                     NOT NULL NUMBER
 CNAME                                     NOT NULL VARCHAR2(30)
 COLTYPE                                            VARCHAR2(106)
 WIDTH                                     NOT NULL NUMBER
 SCALE                                              NUMBER
 PRECISION                                          NUMBER
 NULLS                                              VARCHAR2(19)
 DEFAULTVAL                                         LONG
 CHARACTER_SET_NAME                                 VARCHAR2(44)

Answer 1

SELECT * from col where tname = 'table_name'

Answer 2

select * from ALL_TAB_COLUMNS where table_name = 'table_name'