Question

mysql5.5中表的结构

表名：

id:
name:
detail:

这里甚至改变了表格：

ALTER TABLE tablename MODIFY name VARCHAR(255) CHARACTER SET utf8 COLLATE utf8_persian_ci NOT NULL;

OR

ALTER TABLE `tablename` CHANGE `name` `name` VARCHAR(255) CHARACTER SET utf8 COLLATE utf8_persian_ci NOT NULL DEFAULT NOT NULL;

插入值后

：

INSERT INTO `databasename`.`tablename` (`id`, `name`, `detail`) VALUES (NULL, '', 'asdfasfdadsfadsfafd');

查询已成功运行，没有向表中添加错误行，

我怎样才能防止这种空或空。

问候

Answer 1

试试这个：

ALTER TABLE tablename 
MODIFY COLUMN name VARCHAR(255) CHARACTER SET utf8 COLLATE utf8_persian_ci NOT NULL CHECK (name <> '');

样本：

mysql> create table tablename(id int(2) not null, something varchar(25) null, primary key(id));
Query OK, 0 rows affected (0.15 sec)
mysql> insert into tablename values(0,'hello');
Query OK, 1 row affected (0.38 sec)

mysql> insert into tablename values(1,'salut');
Query OK, 1 row affected (0.31 sec)

mysql> select * from tablename;
+----+-----------+
| id | something |
+----+-----------+
|  0 | hello     |
|  1 | salut     |
+----+-----------+
2 rows in set (0.00 sec)

现在，我运行UPDATE命令：

mysql> ALTER TABLE tablename  MODIFY COLUMN something VARCHAR(255) CHARACTER SET utf8 COLLATE utf8_persian_ci NOT NULL;
Query OK, 2 rows affected (0.70 sec)
Records: 2  Duplicates: 0  Warnings: 0

我插入普通行：

mysql> insert into tablename values(2,'france');
Query OK, 1 row affected (0.29 sec)

但它不允许我插入NULL值：

mysql> insert into tablename values(3,NULL);
ERROR 1048 (23000): Column 'something' cannot be null

我检查确定：

mysql> select * from tablename;
+----+-----------+
| id | something |
+----+-----------+
|  0 | hello     |
|  1 | salut     |
|  2 | france    |
+----+-----------+
3 rows in set (0.00 sec)

MYSQL已将列设置为非null但仍接受空值

1 个答案: