106.Oracle数据库SQL开发之表——向表中添加注释

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106.Oracle数据库SQL开发之表——向表中添加注释

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注释有助于记住表或列的用途。使用COMMENT语句可以为表或列添加注释。

例如：

store@PDB1> comment on table order_status2 is'order_status2 stores the state of an order';

Comment created.

为列添加注释：

store@PDB1> comment on columnorder_status2.last_modified is 'last_modified stores the date and time theorder was modified last';

Comment created.

1. 获得表的注释

通过user_tab_comments视图可以获得有关表的注释：

store@PDB1> select * from user_tab_comments wheretable_name='ORDER_STATUS2';

TABLE_NAME

----------------------------------------------------------------------------------------------------

TABLE_TYPE

-----------

COMMENTS

----------------------------------------------------------------------------------------------------

ORIGIN_CON_ID

-------------

ORDER_STATUS2

TABLE

order_status2 stores the state of an order

通过user_col_comments视图可以获得有关列的注释。

store@PDB1> select * from user_col_comments wheretable_name='ORDER_STATUS2';

TABLE_NAME

----------------------------------------------------------------------------------------------------

COLUMN_NAME

----------------------------------------------------------------------------------------------------

COMMENTS

----------------------------------------------------------------------------------------------------

ORIGIN_CON_ID

-------------

ORDER_STATUS2

STATUS

ORDER_STATUS2

LAST_MODIFIED

last_modified stores the date and time theorder was modified last

ORDER_STATUS2

MODIFIED_BY

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