MySQL 的安全更新模式

MySQL 的安全更新模式2013-10-30删除mysql 的一个表的数据的时候报告如下错误：

mysql> delete from upload_images;
ERROR 1175 （HY000）: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column


mysql> show variables like "%sql_safe%";
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| sql_safe_updates | ON |
+------------------+-------+
1 row in set （0.00 sec）

mysql> set sql_safe_updates=0;

Query OK, 0 rows affected （0.00 sec）

mysql> show variables like "%sql_safe%";
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| sql_safe_updates | OFF |
+------------------+-------+
1 row in set （0.00 sec）
mysql> delete from upload_images;
Query OK, 505 rows affected （0.01 sec）

然后再启用safe mode

mysql> set sql_safe_updates=1;