MySql数据库中的主键和Oracle数据库中的如何通过sql确认那个字段是主键?

oracle写法：

select a.constraint_name, a.column_name
from user_cons_columns a, user_constraints b
where a.constraint_name = b.constraint_name
and b.constraint_type = 'P'
and a.table_name = 'AA'

Mysql写法

  t.TABLE_NAME,
  c.COLUMN_NAME
FROM
  INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS t,

  information_schema.KEY_COLUMN_USAGE AS c
WHERE
  t.TABLE_NAME = c.TABLE_NAME
  -- AND t.TABLE_SCHEMA = 'TABLE_NAME'
  AND t.CONSTRAINT_TYPE = 'PRIMARY KEY';

注意：table_name都要大写。

import java.util.*; import java.io.*; class SequenceDemo{ public static void main(String[] args) { Vectorv=new Vector(); v.add(new FileInputStream("c:"+File.separator+"1.txt")); v.add(new FileInputStream("c:"+File.separator+"2.txt")); v.add(new FileInputStream("c:"+File.separator+"3.txt")); Enumerationen=v.elements(); SequenceInputStream sis=new SequenceInputStream(en); } public static void sop(Object obj){ System.out.println(obj); } }

select column_key
from information_schema.columns
where table_schema='数据库名' and table_name='表名' and column_name='列名';