Multitenancy is the ability by which an application can act (and seem) different when observed in different ways. Think, for example, of a website that displays a different look and feel when it is accessed as
http://xyz.net. Here, we are talking about the same physical site having two different domain names bound to it,
xyz.net, which are the tenants.
When it comes to relational databases, there are essentially three techniques for achieving multitenancy: