ORACLE資料庫對比表結構

有時候會有某種需求：需要對比兩個表的表結構是否一致，有時候甚至是整個資料庫所有表的表結構對比......。表結構對比無非就是欄位名、字段型別、字段資料型別、以及欄位的順序的對比。如果需要對比表結構，可以通過下面簡單的指令碼實現：

select m.owner

,m.table_name

,m.column_id

,m.column_name

,m.data_type

,m.data_length

,n.owner

,n.table_name

,n.column_id

,n.column_name

,n.data_type

,n.data_length

from

select owner

,table_name

,column_id

,column_name

,data_type

,data_length

from dba_tab_columns

where owner=&owner_a

and table_name=&table_name_a

) m left
join

select owner

,table_name

,column_id

,column_name

,data_type

,data_length

from dba_tab_columns

where owner=&owner_b

and table_name=&table_name_b

) n on  m.column_id =n.column_id

and m.column_name = n.column_name

and m.data_type = n.data_type

and m.data_length= n.data_length

order
by m.table_name, m.column_id;

但是如果a表與b表前面的字段一致，然而b表有一些額外的字段，那麼上面的sql（左連線）就會查不出兩者之間結構的不同。此時需要使用右連線才能對比出真正的表結構。所以如果需要對比兩者的表結構是否一致，最好左連線查一次，右連線查一次。才能真正的確認兩者的表結構的異同。

select m.owner

,m.table_name

,m.column_id

,m.column_name

,m.data_type

,m.data_length

,n.owner

,n.table_name

,n.column_id

,n.column_name

,n.data_type

,n.data_length

from

select owner

,table_name

,column_id

,column_name

,data_type

,data_length

from dba_tab_columns

where owner=&owner_a

and table_name=&table_name_a

) m right
join

select owner

,table_name

,column_id

,column_name

,data_type

,data_length

from dba_tab_columns

where owner=&owner_b

and table_name=&table_name_b

) n on  m.column_id =n.column_id

and m.column_name = n.column_name

and m.data_type = n.data_type

and m.data_length= n.data_length

order
by m.table_name, m.column_id;