When a business manager invests in new or modified software, he or she expects business results from that investment. Sadly, more often than not, they don't get that. They may get a technically brilliant system, but if that system's architecture isn't based on the architecture of the business, or on business goals and strategy – then it's still a failure.
Data architecture is an area in which the optimal degree of isolation for a SaaS application can vary significantly depending on technical and business considerations. Experienced data architects are used to considering a broad spectrum of choices when designing an architecture to meet a specific set of challenges, and SaaS is certainly no exception. We shall examine three broad approaches, each of which lies at a different location in the continuum between isolation and sharing