oracle 查询表字段及表数据

资料参考：
https://www.cnblogs.com/nayitian/archive/2013/08/02/3231784.html

https://blog.csdn.net/yangzjchn/article/details/81019449

表内字段内容

select 
case when col.column_name = utc.column_name then '1' else '0' end isKey, 
utc.column_name name, utc.data_type type,ucc.comments remark from user_tab_columns utc, user_col_comments ucc，user_constraints con, user_cons_columns col 
where 
utc.table_name = ucc.table_name 
and 
utc.column_name = ucc.column_name 
and 
utc.table_name = col.table_name 
and 
con.constraint_name=col.constraint_name and con.constraint_type='P' 
and 
utc.table_name = '表名' 
order by column_id

表内容

select 
t.table_name as name, c.comments as remark, o.created as createTime 
from 
user_tables t , USER_OBJECTS o, user_tab_comments c "
where 
t.table_name = o.object_name 
and 
t.table_name = c.table_name 

1. 查询表基本信息

select
    utc.column_name,utc.data_type,utc.data_length,utc.data_precision,
    utc.data_Scale,utc.nullable,utc.data_default,ucc.comments
from
    user_tab_columns utc,user_col_comments ucc
where
    utc.table_name = ucc.table_name
    and utc.column_name = ucc.column_name
    and utc.table_name = 'BBSDETAIL'
order by
    column_id;

order by column_id的意义是使得结果按照设计数据结构时的顺序显示。

输出：

DETAIL_ID NUMBER 22 N 明细编号
TITLE VARCHAR2 100 N 标题
CATEGORY_ID NUMBER 22 N 分类编号（外键）
DISTRICT_ID NUMBER 22 N 城市编号（外键）
ADDRESS VARCHAR2 500 Y 地址

2. 查询表主键

select
 col.column_name
from
 user_constraints con,user_cons_columns col
where
 con.constraint_name=col.constraint_name and con.constraint_type='P'
 and col.table_name='BBSDETAIL';

输出：

DETAIL_ID

3. 查询表外键

select
 distinct(ucc.column_name) column_name,rela.table_name,rela.column_name column_name1
from
 user_constraints uc,user_cons_columns ucc,
 (select t2.table_name,t2.column_name,t1.r_constraint_name from user_constraints t1,user_cons_columns t2 where t1.r_constraint_name=t2.constraint_name and t1.table_name='BBSDETAIL') rela
where
 uc.constraint_name=ucc.constraint_name
 and uc.r_constraint_name=rela.r_constraint_name
 and uc.table_name='BBSDETAIL';

输出：

CATEGORY_ID BBSCATEGORY CATEGORY_ID
DISTRICT_ID BBSDISTRICT DISTRICT_ID