(FORTUNE Magazine) – SOMETIMES YOU don't know if a decision was right for months or years; sometimes it is forever ambiguous. But I knew my decision to push for a centralized pharmacy database ahead of schedule was right the day after Hurricane Katrina hit.

I'm in charge of information technology at Wal-Mart, and one of the projects we had on our to-do list last March was to pull together all the prescription information into a national database. The idea was to allow customers to fill their prescriptions at any Wal-Mart. Some 90% of the prescriptions we fill are paid for by insurance, so what causes customers to go to one pharmacy over another isn't price. We needed to offer customers other advantages, and this database was one of them.

The team in charge of this effort said they could finish by the fall. I stopped the meeting and challenged them. I said, "Let's look at what this means to our customers and what this will mean to our business. There's got to be a way to do it sooner." Then I gave them a very aggressive date: the end of April. The team was shell-shocked. They didn't see how it could be done.

But I wanted them to think differently about what they were doing. So we pulled together people from across the IT division who hadn't had any experience with the project. They wouldn't be too close to it and would bring in fresh ideas. They went off for two days and came up with a solution to complete the project faster--and at less cost, because it would take less time to do. And yes, they finished it by the end of April.

That became very important after Hurricane Katrina because it meant that any store could fill prescriptions. We had 12 stores in the New Orleans area and a couple in Mississippi that were destroyed or closed. We were able to say, "If you've ever gotten a prescription filled by Wal-Mart, you can go into any store and fill it now."

It also gave us the ability to send in mobile pharmacies because they too had access to all the prescription histories. Our system is built in such a way that pharmacists can work over a PC screen: We capture the physical image of the prescription and the image of the filled bottle. So we had pharmacists set up remotely in Arkansas working with the mobile pharmacies to help fill prescriptions. If we hadn't finished the project earlier, we wouldn't have had that capability.