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Accepted
David LeBauer
Asked: 2012-09-20 09:40:23 +0800 CST

打印带有注释的表格文档？

  • 772

我有一个 MySQL 数据库，我使用 MySQL Workbench 将文本插入到许多列和表的“注释”字段中；计划是将文档存储在数据库中。

但是，我不知道如何 a) 向列添加评论，或者更重要的是 b) 检索此信息。

我浏览了关于Describe、Show Columns和Show Extensions的有限 MySQL 文档。

例如，我想返回这个：

mysql> describe dogs;

+----------------+-------------------------------+
| Field          | Comment                       | 
+----------------+-------------------------------+
| id             | primary key                   | 
| Name           | Dog's name                    | 
| species_id     | Foreign key to look up species|

代替

mysql> describe dogs;
+----------------+--------------+------+-----+---------+----------------+
| Field          | Type         | Null | Key | Default | Extra          |
+----------------+--------------+------+-----+---------+----------------+
| id             | int(11)      | NO   | PRI | NULL    | auto_increment | 
| name           | varchar (255)| YES  | MUL | NULL    |                | 
| species_id     | int(11)      | YES  | MUL | NULL    |                |

虽然这样做：

mysql> describe dogs;

mysql> describe dogs;
+----------------+--------------+------+-----+---------+----------------+-------------------------------+
| Field          | Type         | Null | Key | Default | Extra          | Comment                       | 
+----------------+--------------+------+-----+---------+----------------+-------------------------------+
| id             | int(11)      | NO   | PRI | NULL    | auto_increment |                               |
| name           | varchar (255)| YES  | MUL | NULL    |                | Dog's name                    |  
| species_id     | int(11)      | YES  | MUL | NULL    |                | Foreign key to look up species|

我有哪些选择？MySQL 工作台是否导出此类文档？

mysql mysql-workbench

1 个回答

  1. Best Answer

    您可以使用普通的 DML/DDL 执行此操作。

    创建一个带有注释的表：

    mysql> create table testcomments ( 
    -> col1 integer comment 'comment on integer column',
    -> col2 varchar(20) comment 'comment on varchat col');
Query OK, 0 rows affected (0.01 sec)

    从数据字典中选择信息（文档链接）：

    mysql> select column_name, column_comment
    -> from INFORMATION_SCHEMA.COLUMNS
    -> where TABLE_NAME = 'testcomments';
+-------------+---------------------------+
| column_name | column_comment            |
+-------------+---------------------------+
| col1        | comment on integer column |
| col2        | comment on varchat col    |
+-------------+---------------------------+
2 rows in set (0.00 sec)

mysql>

    添加/修改评论：

    mysql> alter table testcomments
    -> change column col1
    -> col1 integer comment 'modified comment on integer column';

Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select column_name, column_comment  from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = 'testcomments';
+-------------+------------------------------------+
| column_name | column_comment                     |
+-------------+------------------------------------+
| col1        | modified comment on integer column |
| col2        | comment on varchat col             |
+-------------+------------------------------------+
2 rows in set (0.00 sec)

mysql>

    修改表格注释：

    mysql> alter table testcomments comment 'foo';
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql>

    查看表格评论：

    mysql> select TABLE_COMMENT
    -> from INFORMATION_SCHEMA.TABLES
    -> where TABLE_NAME = 'testcomments';
+---------------+
| TABLE_COMMENT |
+---------------+
| foo           |
+---------------+
1 row in set (0.00 sec)

mysql>
    • 4

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