In designing an information system for some work process, it has to be done in phases whereby there is one centralise portal linking all these information systems together. The backend database is ideally one database whereby all information systems are updating particular sections of tables in it. These tables are connected to each other in some way where you have primary keys and foreign keys.
Funny thing is, users don’t really comprehend a programmer’s perspective in designing an information system. “How hard can it be!” is what they usually say. But users don’t comprehend what programmers go through when there are add ons from the original design.
It’s like having built a big round metal container for an oil refinery. A crane of 100 tons comes in and places the container at the site. A few years later there seems to be holes in the container, so the maintenance team comes in and patches it by just cutting a piece of metal and cover the hole by welding to the original structure. After doing that for so many years, then one day they decide to scrap the structure. So the maintenance team comes in with the 100 ton and lifts the structure. However the crane and structure topples. Why does it topple? It topples because all the metals covering the holes of the original structure makes the structure heavier than it originally was. The centre of mass of the structure is no longer the same due to the constant patches and add ons.
The same goes with implementing databases. If the database design originally did not consider including the idea in the original design and patches of add ons over the years are put in place, the database gets more heavier and it will be slower for people to access. This is invisible to the users and so users don’t understand the pain system analyts have to go through when users cannot decide what they really need.
