I'm contemplating a project and trying to work out the logistics:

I have a client that owns 3+ companies. Each would be equipped with the same custom CMS. One solution is to create a database for each application. Problem is, internal administrators would need multiple login names to control each website. 

A better solution would be to have a client database, and a content database. The user would validate his/her credentials through the client database, thus gaining access to the content.

I see two ways of doing this 1. Using 1 database for clients, and 3 databases for the content. 2. Use 1 database for everything.

Is it possible to validate a user using one database while pulling content from another?

hmmmm... great question. I would look to be a minimalist when it came to administrative work. Admins, although we love them are people who love simple management. I'm a big fan of the microsofts built in members db. I manage access to two different sites with different content from different db's with this setup. Since the security is handled by the members db, i can use it against multiple sites using different db's!!

So admins can manage the rights through the members db, one point of administration!!

Keeping it simple is the objective.

Can you explain the members DB? Is this a 3rd database that you validate against, then manipulate data in one of the other content databases?

Thanks for your help 

 Its better to go with a single database for the clients credential validations and seperate database for the contents

The memebrs db(memberships Database) allows developers to not have to figure out how to build a authentication and authorization db. They've prebuilt it! We as developers just focus on how we want to use that database. It come preset with all the security "stuff" you'd want on a site like: uid, pwd, secret question and answer, email address, etc(alot more that i don't want to type :))...plus it allows you to provide your own customizations like it you want to collect points for each user for the number of questions answered like here at asp.net.

It allows us to not have to figure out the internal workings of our security and focus on the information and administration of our sites! It has been great for me and sites that i work with.

The concept is to have a authentication/authorization db and content db's. 

So my security is handled outside of the content db's, that way we're managing security seporate from content! I can have 50 sites using my "Members db" and 50 seporate "Content db's"(might be a bit much) to manage the information on each site. But only one members db. Think of how live/passport works, one login for all of the different sites and services they provide. You can login to hotmail, connect, Mesh Live, partners site, technet, msdn all with one login.

On the flip side you can have users of different site who will never enter into each others sites also maintained in the same members db! 

In summary security is different from content and should be treated as such...

Hope this helps!

That is brilliant, exactly what I am looking for. Initially I was going to build my own, but why reinvent the wheel if there is an existing solution. I will look into this and see what customization options it brings.

 
Thanks for your help.