关于Oracle与SqlServer中获取所有字段、主键、外键的sql语句

--oracle:
--查询某个表中的字段名称、类型、精度、长度、是否为空
select COLUMN_NAME,DATA_TYPE,DATA_PRECISION,DATA_SCALE,NULLABLE 
from user_tab_columns 
where table_name ='YourTableName'
--查询某个表中的主键字段名
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 = 'YourTableName'
--查询某个表中的外键字段名称、所引用表名、所应用字段名
select distinct(col.column_name),r.table_name,r.column_name 
from 
user_constraints con,
user_cons_columns col, 
(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='YourTableName'
 ) r 
where con.constraint_name=col.constraint_name 
and con.r_constraint_name=r.r_constraint_name 
and con.table_name='YourTableName' 
--SQLServer中的实现：
--字段：
SELECT c.name,t.name,c.xprec,c.xscale,c.isnullable 
FROM systypes t,syscolumns c 
WHERE t.xtype=c.xtype 
AND c.id = (SELECT id FROM sysobjects WHERE name='YourTableName') 
ORDER BY c.colid

--主键（参考SqlServer系统存储过程sp_pkeys）：
select COLUMN_NAME = convert(sysname,c.name)               
from                                                       
sysindexes i, syscolumns c, sysobjects o                   
where o.id = object_id('[YourTableName]')                  
and o.id = c.id                                            
and o.id = i.id                                            
and (i.status & 0x800) = 0x800                             
and (c.name = index_col ('[YourTableName]', i.indid,  1) or     
     c.name = index_col ('[YourTableName]', i.indid,  2) or     
     c.name = index_col ('[YourTableName]', i.indid,  3) or     
     c.name = index_col ('[YourTableName]', i.indid,  4) or     
     c.name = index_col ('[YourTableName]', i.indid,  5) or     
     c.name = index_col ('[YourTableName]', i.indid,  6) or     
     c.name = index_col ('[YourTableName]', i.indid,  7) or     
     c.name = index_col ('[YourTableName]', i.indid,  8) or     
     c.name = index_col ('[YourTableName]', i.indid,  9) or     
     c.name = index_col ('[YourTableName]', i.indid, 10) or     
     c.name = index_col ('[YourTableName]', i.indid, 11) or     
     c.name = index_col ('[YourTableName]', i.indid, 12) or     
     c.name = index_col ('[YourTableName]', i.indid, 13) or     
     c.name = index_col ('[YourTableName]', i.indid, 14) or     
     c.name = index_col ('[YourTableName]', i.indid, 15) or     
     c.name = index_col ('[YourTableName]', i.indid, 16)       
     )

--外键：
select t1.name,t2.rtableName,t2.name 
from 
(select col.name, f.constid as temp 
 from syscolumns col,sysforeignkeys f 
 where f.fkeyid=col.id 
 and f.fkey=col.colid 
 and f.constid in 
 ( select distinct(id)  
   from sysobjects 
   where OBJECT_NAME(parent_obj)='YourTableName' 
   and xtype='F' 
  ) 
 ) as t1 , 
(select OBJECT_NAME(f.rkeyid) as rtableName,col.name, f.constid as temp 
 from syscolumns col,sysforeignkeys f 
 where f.rkeyid=col.id 
 and f.rkey=col.colid 
 and f.constid in 
 ( select distinct(id) 
   from sysobjects 
   where OBJECT_NAME(parent_obj)='YourTableName' 
   and xtype='F' 
 ) 
) as t2 
where t1.temp=t2.temp