用sql比较两个库是否一致

比较两个数据库，可以用工具，比如toad等，也可以自己写存储过程来实现，偶介绍一个用sql来核对表结构是否一致，以此类推，大家可以写出对比索引是否一致，对比约束是否一致的sql，该sql的缺点就是只能查出差异，却不知是那个表引起的：

select case when a.cnt = b.cnt then '两个库结构一致'
when a.cnt <> b.cnt then '两个库结构不一致' end
from (select count(*) as cnt
from dba_tab_columns t1, dba_tab_colums@lnk_db2 t2
where t1.owner = 'TAOBAO'
and t1.owner = t2.owner
and t1.table_name = t2.table_name
and t1.column_name = t2.column_name
and t1.data_type = t2.data_type
and t1.data_length = t2.data_length
and t1.nullable = t2.nullable
and nvl(t1.data_precision, 0) = nvl(t2.data_precision, 0)
and nvl(t1.data_scale, 0) = nvl(t2.data_scale, 0)) a,
(select count(*) as cnt
from dba_tab_columns
where owner = 'TAOBAO') b