What is the best way to manage permissions for a w

Question

I'm considering the best way to design a permissions system for an "admin" web application. The application is likely to have many users, each of whom could be assigned a certain role; some of these users could be permitted to perform specific tasks outside the role.

I can think of two ways to design this: one, with a "permissions" table with a row for every user, and boolean columns, one for each task, that assign them permissions to perform those tasks. Like this:

User ID          Manage Users     Manage Products     Manage Promotions     Manage Orders
1                true             true                true                  true
2                false            true                true                  true
3                false            false               false                 true

Another way I thought of was to use a bit mask to store these user permissions. This would limit the number of tasks that could be managed to 31 for a 32-bit signed integer, but in practice we're unlikely to have more than 31 specific tasks that a user could perform. This way, the database schema would be simpler, and we wouldn't have to change the table structure every time we added a new task that would need access control. Like this:

User ID          Permissions (8-bit mask), would be ints in table
1                00001111
2                00000111
3                00000001

What mechanisms have people here typically used, and why?

Thanks!

Answer 1

You could use Active Directory or another LDAP implementation if you're in a managed environment. That way the security groups, which determine permissions can be managed by first line support, using a technology they're most likely already familiar with.

If your app is shrink wrapped then +1 for Levi Rosol's suggestion of normalising the database so that you can have an extensible data model in your app.

Answer 2

how about creating a Permission table, then a UserPermission table to store the relationships?

You'll never have to modify the structure again, and you have the ability to add as many permissionss as you wish.