Thanks for the reply NogDog. I had actually looked at the Rails/PostgreSQL option as well but opted for PHP simply based on the amount of community based support and content available.
I am looking to develop commercial applications that are based in the cloud. In the beginning I will be primarily targeting SMB sized businesses that need Enterprise level solutions without the Enterprise level budget. None of this is shocking I am sure, but I at least want to make sure I am heading in the right direction.
Based on the above scenario, should I be planning that each company would have their own DB, or am I ok to have multiple customers on the same DB but separated by permissions. If that was the situation, would it be done by a separate table for each customer within the database and assign permissions to users accordingly, or would they simply all use the same tables, but differentiated in a different way.
Any advice is very much appreciated!