ORACLE数据库对比表结构

有时候会有某种需求：需要对比两个表的表结构是否一致，有时候甚至是整个数据库所有表的表结构对比......。表结构对比无非就是字段名、字段类型、字段数据类型、以及字段的顺序的对比。如果需要对比表结构，可以通过下面简单的脚本实现：

[code]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表与B表前面的字段一致，然而B表有一些额外的字段，那么上面的SQL（左连接）就会查不出两者之间结构的不同。此时需要使用右连接才能对比出真正的表结构。所以如果需要对比两者的表结构是否一致，最好左连接查一次，右连接查一次。才能真正的确认两者的表结构的异同。

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;