MySQL: Select 基于二元权限的导航项目
MySQL: Select Items for a navigation based on binary rights
我已经建立了一个简单的权限管理,基于二进制加法。
我数据库中的每个导航条目都遵循以下结构:
等等..
每个用户都有自己的访问级别..
用户 = 3(1+2 - 访问级别)
管理员 = 15 (1+2+4+8)
到目前为止一切顺利。我现在的问题是,select 通过 MySQL 从 table 中获取相应的字段。我的第一个方法是 select 所有 access_level <= 用户总和 access_level 的条目,但很快我意识到这还包括其他具有较低 access_level 的页面].
您必须使用二进制 AND 来查看位是否已设置。您也可以使用设置字段。它也是一个命名每个位的位域。
然后像这样:
WHERE (access_level & 15);
示例 - 创建 table 并填充
mysql> CREATE TABLE `access_table` (
-> `id` INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
-> `item_text` VARCHAR(32) DEFAULT NULL,
-> `url` VARCHAR(32) DEFAULT NULL,
-> `access_level` SET('home','help','backend','admin') DEFAULT NULL,
-> PRIMARY KEY (`id`)
-> ) ENGINE=INNODB DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0,02 sec)
mysql>
mysql> INSERT INTO `access_table` (`id`, `item_text`, `url`, `access_level`)
-> VALUES
-> (1, 'home', '/home', 'home'),
-> (2, 'help', '/help', 'help'),
-> (3, 'backend', '/backend', 'backend'),
-> (4, 'hoadmpage', '/admin', 'admin');
Query OK, 4 rows affected (0,00 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql>
示例 - 显示所有行和 select 一些通过位
mysql> SELECT *,access_level+0 FROM ACCESS_TABLE;
+----+-----------+----------+--------------+----------------+
| id | item_text | url | access_level | access_level+0 |
+----+-----------+----------+--------------+----------------+
| 1 | home | /home | home | 1 |
| 2 | help | /help | help | 2 |
| 3 | backend | /backend | backend | 4 |
| 4 | hoadmpage | /admin | admin | 8 |
+----+-----------+----------+--------------+----------------+
4 rows in set (0,00 sec)
mysql>
mysql> SELECT *,access_level+0
-> FROM ACCESS_TABLE
-> WHERE (access_level & 15);
+----+-----------+----------+--------------+----------------+
| id | item_text | url | access_level | access_level+0 |
+----+-----------+----------+--------------+----------------+
| 1 | home | /home | home | 1 |
| 2 | help | /help | help | 2 |
| 3 | backend | /backend | backend | 4 |
| 4 | hoadmpage | /admin | admin | 8 |
+----+-----------+----------+--------------+----------------+
4 rows in set (0,00 sec)
mysql> SELECT *,access_level+0
-> FROM ACCESS_TABLE
-> WHERE (access_level & 7);
+----+-----------+----------+--------------+----------------+
| id | item_text | url | access_level | access_level+0 |
+----+-----------+----------+--------------+----------------+
| 1 | home | /home | home | 1 |
| 2 | help | /help | help | 2 |
| 3 | backend | /backend | backend | 4 |
+----+-----------+----------+--------------+----------------+
3 rows in set (0,00 sec)
mysql> SELECT *,access_level+0
-> FROM ACCESS_TABLE
-> WHERE (access_level & 9);
+----+-----------+--------+--------------+----------------+
| id | item_text | url | access_level | access_level+0 |
+----+-----------+--------+--------------+----------------+
| 1 | home | /home | home | 1 |
| 4 | hoadmpage | /admin | admin | 8 |
+----+-----------+--------+--------------+----------------+
2 rows in set (0,00 sec)
mysql>
我已经建立了一个简单的权限管理,基于二进制加法。
我数据库中的每个导航条目都遵循以下结构:
每个用户都有自己的访问级别..
用户 = 3(1+2 - 访问级别) 管理员 = 15 (1+2+4+8)
到目前为止一切顺利。我现在的问题是,select 通过 MySQL 从 table 中获取相应的字段。我的第一个方法是 select 所有 access_level <= 用户总和 access_level 的条目,但很快我意识到这还包括其他具有较低 access_level 的页面].
您必须使用二进制 AND 来查看位是否已设置。您也可以使用设置字段。它也是一个命名每个位的位域。
然后像这样:
WHERE (access_level & 15);
示例 - 创建 table 并填充
mysql> CREATE TABLE `access_table` (
-> `id` INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
-> `item_text` VARCHAR(32) DEFAULT NULL,
-> `url` VARCHAR(32) DEFAULT NULL,
-> `access_level` SET('home','help','backend','admin') DEFAULT NULL,
-> PRIMARY KEY (`id`)
-> ) ENGINE=INNODB DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0,02 sec)
mysql>
mysql> INSERT INTO `access_table` (`id`, `item_text`, `url`, `access_level`)
-> VALUES
-> (1, 'home', '/home', 'home'),
-> (2, 'help', '/help', 'help'),
-> (3, 'backend', '/backend', 'backend'),
-> (4, 'hoadmpage', '/admin', 'admin');
Query OK, 4 rows affected (0,00 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql>
示例 - 显示所有行和 select 一些通过位
mysql> SELECT *,access_level+0 FROM ACCESS_TABLE;
+----+-----------+----------+--------------+----------------+
| id | item_text | url | access_level | access_level+0 |
+----+-----------+----------+--------------+----------------+
| 1 | home | /home | home | 1 |
| 2 | help | /help | help | 2 |
| 3 | backend | /backend | backend | 4 |
| 4 | hoadmpage | /admin | admin | 8 |
+----+-----------+----------+--------------+----------------+
4 rows in set (0,00 sec)
mysql>
mysql> SELECT *,access_level+0
-> FROM ACCESS_TABLE
-> WHERE (access_level & 15);
+----+-----------+----------+--------------+----------------+
| id | item_text | url | access_level | access_level+0 |
+----+-----------+----------+--------------+----------------+
| 1 | home | /home | home | 1 |
| 2 | help | /help | help | 2 |
| 3 | backend | /backend | backend | 4 |
| 4 | hoadmpage | /admin | admin | 8 |
+----+-----------+----------+--------------+----------------+
4 rows in set (0,00 sec)
mysql> SELECT *,access_level+0
-> FROM ACCESS_TABLE
-> WHERE (access_level & 7);
+----+-----------+----------+--------------+----------------+
| id | item_text | url | access_level | access_level+0 |
+----+-----------+----------+--------------+----------------+
| 1 | home | /home | home | 1 |
| 2 | help | /help | help | 2 |
| 3 | backend | /backend | backend | 4 |
+----+-----------+----------+--------------+----------------+
3 rows in set (0,00 sec)
mysql> SELECT *,access_level+0
-> FROM ACCESS_TABLE
-> WHERE (access_level & 9);
+----+-----------+--------+--------------+----------------+
| id | item_text | url | access_level | access_level+0 |
+----+-----------+--------+--------------+----------------+
| 1 | home | /home | home | 1 |
| 4 | hoadmpage | /admin | admin | 8 |
+----+-----------+--------+--------------+----------------+
2 rows in set (0,00 sec)
mysql>