<p>一个采用多对多关系的一个用户与一组用户对系统的权限的示例数据库结构：</p>
Users表：
| UserID | Full Name | Password | Active |
| JohnD | John Doe | Jfz9..nm3 | 1 |
| SamS | Sam Spade | klk93)md | 1 |
中间表UserPermissions：
| UserID | Permission ID |
| JohnD | 1 |
| JohnD | 2 |
| JohnD | 3 |
| SamS | 1 |
| SamS | 2 |
| SamS | 3 |
| SamS | 4 |
Permissions表：
| Permission ID | Description |
| 1 | Read |
| 2 | Insert |
| 3 | Update |
| 4 | Delete |