每当插入一个记录时候 假设没有明确字段赋值 则自动赋予默认值;
mysql> CREATE TABLE eight(
-> id SMALLINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-> username VARCHAR(20) NOT NULL UNIQUE KEY,
-> sex ENUM ("1","2","3") DEFAULT'3' DEFAULT设置默认值;
-> );
Query OK, 0 rows affected (0.01 sec)
mysql> SHOW COLUMNS FROM eight;
+----------+----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+----------------------+------+-----+---------+----------------+
| id | smallint(5) unsigned | NO | PRI | NULL | auto_increment |
| username | varchar(20) | NO | UNI | NULL | |
| sex | enum('1','2','3') | YES | | 3 | |
+----------+----------------------+------+-----+---------+----------------+
3 rows in set (0.03 sec)
mysql> INSERT EIGHT (USERNAME)VALUES('feiyu');
Query OK, 1 row affected (0.00 sec)
mysql> SELECT * FROM eight;
+----+----------+------+
| id | username | sex |
+----+----------+------+
| 1 | feiyu | 3 |
+----+----------+------+
1 row in set (0.00 sec)
mysql>
DEFAULT 默认值
猜你喜欢
转载自blog.csdn.net/feiyucity/article/details/82974504
今日推荐
周排行