赞
踩
列属性:列属性又称之为字段属性,在mysql中一共有6个属性:null,默认值,列描述,主键,唯一键和自动增长
null属性:代表字段为空
如果对应的值为YES表示该字段可以为NULL
- mysql> desc int_data;
- +-------+------------------------------+------+-----+---------+-------+
- | Field | Type | Null | Key | Default | Extra |
- +-------+------------------------------+------+-----+---------+-------+
- | int_1 | tinyint(4) | YES | | NULL | |
- | int_2 | smallint(6) | YES | | NULL | |
- | int_3 | mediumint(9) | YES | | NULL | |
- | int_4 | int(11) | YES | | NULL | |
- | int_5 | bigint(20) | YES | | NULL | |
- | int_6 | tinyint(3) unsigned | YES | | NULL | |
- | int_7 | tinyint(3) unsigned zerofill
Copyright © 2003-2013 www.wpsshop.cn 版权所有,并保留所有权利。