MySQL 即使在必填字段不存在时也允许插入

Question

我有一个数据库 table 供具有与此类似设置的用户使用：

+---------------------+--------------+------+-----+------------+----------------+
| Field               | Type         | Null | Key | Default    | Extra          |
+---------------------+--------------+------+-----+------------+----------------+
| id_user             | int(5)       | NO   | PRI | NULL       | auto_increment |
| login               | varchar(50)  | NO   |     |            |                |
| password            | varchar(50)  | NO   |     |            |                |
| address             | varchar(255) | NO   |     | NULL       |                |
+---------------------+--------------+------+-----+------------+----------------+

由于地址字段设置为非空并且默认为空，这应该有效地使地址字段成为必需的，对吧？

但是当我执行如下查询时：

INSERT INTO mydatabase.users
SET
    mydatabase.users.login='test_username',
    mydatabase.users.password='test_password'

它成功地拯救了用户，没有抱怨地址字段被设置为空space。

这可能是什么原因造成的？我预计在这种情况下会出现错误。我用 MySQL 5.5 和 5.6 试过了。

Answer 1

Strict SQL mode在配置文件中没有启用，因此mysql放宽了对数据插入的某些控制：

Strict mode controls how MySQL handles invalid or missing values in data-change statements such as INSERT or UPDATE. A value can be invalid for several reasons. For example, it might have the wrong data type for the column, or it might be out of range. A value is missing when a new row to be inserted does not contain a value for a non-NULL column that has no explicit DEFAULT clause in its definition. (For a NULL column, NULL is inserted if the value is missing.) Strict mode also affects DDL statements such as CREATE TABLE.

MySQL 即使在必填字段不存在时也允许插入

MySQL allows inserts even when required fields are not present

mysql

required-field

notnull

insert-into