Oracle常用查询（一）

select t.* from product_component_version t; --查看 oracle 产品组件版本

select t.* from user_db_links t; --dblink

select t.* from user_synonyms t; --同义词

select t.* from user_jobs t; --dbms_job

--查询外键
select a.constraint_name   外键约束名,
       b.table_name        外键所在表,
       b.column_name       外键所在列,
       a.r_constraint_name 关联主键名,
       c.table_name        关联表,
       c.column_name       关联表列名,
       a.status,
       a.validated
  from user_constraints a, user_cons_columns b, user_cons_columns c
 where 1 = 1
   and a.constraint_type = upper('r')
   and a.constraint_name = b.constraint_name
   and a.r_constraint_name = c.constraint_name
   and exists (select 1
          from user_tables ut
         where ut.table_name = a.table_name
           and ut.num_rows > 0)
   and 1 = 1
      ---and b.table_name=upper('t_user')---表有哪些外键 
   and c.table_name = upper('t_user') ---表被哪些外键引用
 order by a.table_name, a.constraint_type;