While attending the TAUG meeting a few weeks back, I heard Tom Brantigan use this phrase (which I'd heard before some years ago). He was speaking in reference to business intelligence, data warehousing, and queries. It reminded me of a line I use frequently with my clients, when describing the benefits of a centralized system:
"When a question about anything data-related is asked, the answer should always be the same: Let's look in the database."
Too often, when a question as simple as "Who is on that committee" is asked, we struggle to determine who has the most up-to-date list, or which staff member has that list on their computer. There are many, many questions like these that should always have the same answer: "Let's look in the database." Your central data management system should be your "single version of the truth."