Oracle 查表的信息 dba_segments、all_tables

--查询单张表的使用情况
select segment_name,bytes/1024/1024 || 'm' from dba_segments t where
OWNER = 'user_name'
and t.segment_type='TABLE'

--查表总数
select count(*) as n from (
select t.OWNER,t.TABLE_NAME,t.TABLESPACE_NAME,t.BLOCKS,t.NUM_ROWS,t
from all_tables t where 1=1
AND t.owner LIKE '%user_name%';

--查某个表的所有字段
SELECT TO_CHAR(wm_concat(TC.COLUMN_NAME)) FROM ALL_TAB_COLUMNS TC WHERE table_name=upper('table_name') AND OWNER=upper('user_name');