我在MySQL中设定了属性为非空,但是付值却仍然可以为空,为什么?

Question

如题...求解...

Answer 1

如下例.......
mysql> use example
Database changed
mysql> describe user_message;
+----------------+------------------------------------------------------------+------+-----+---------+----------------+
| Field          | Type                                                       | Null | Key | Default | Extra          |
+----------------+------------------------------------------------------------+------+-----+---------+----------------+
| MessageID      | int(11)                                                    | NO   | PRI | NULL    | auto_increment |
| MessageTitle   | varchar(20)                                                | NO   |     |         |                |
| Class          | enum('user_message','system_message','add_friend_message') | NO   |     |         |                |
| MessageContent | varchar(200)                                               | NO   |     |         |                |
| SendUserID     | varchar(20)                                                | NO   | MUL |         |                |
| ReceiveUserID  | varchar(20)                                                | NO   | MUL |         |                |
| ReadMessage    | tinyint(1)                                                 | NO   |     | 0       |                |
| Date           | date                                                       | NO   |     |         |                |
+----------------+------------------------------------------------------------+------+-----+---------+----------------+
8 rows in set (0.02 sec)mysql> INSERT INTO user_message (MessageTitle,Class,MessageContent,SendUserID,ReceiveUserID,Date) VALUES ('','add_friend_message','','005','007',CURDATE())
;
Query OK, 1 row affected (0.00 sec)