CHAPTER 1
What is a data model?
How do I get there?
Maps, blueprints, data models
Please show me the way
I gave the steering wheel a heavy tap with my hands as I realized that once again, I was completely lost. It was about an hour before dawn, I was driving in France, and an important business meeting awaited me. I spotted a gas station up ahead that appeared to be open. I parked, went inside, and showed the attendant the address of my destination.
I don’t speak French and the attendant didn’t speak English. The attendant did, however, recognize the name of the company I needed to visit. Wanting to help and unable to communicate verbally, the attendant took out a pen and paper. He drew lines for streets, circles for roundabouts along with numbers for exit paths, and rectangles for his gas station and my destination, MFoods. The picture he drew resembled that which appears in Figure 1.1.
Figure 1.1 Simplification of geographic landscape
With this custom-made map, which contained only the information that was relevant to me, I arrived at my address without making a single wrong turn. This map was a model of the actual roads I needed to travel.
A map simplifies a complex geographic landscape in the same way that a data model simplifies a complex information landscape. In many cases, the complexities in the actual data can make those roundabouts in France look ridiculously simple. This chapter explains the data model and its role as an invaluable wayfinding tool. It also introduces the ice cream and business card examples which are carried throughout the text.
Wayfinding Explained
If the term ‘data model’ does not excite you or your business users, try the term ‘wayfinding’ instead. Wayfinding encompasses all of the techniques and tools used by people and animals to find their way from one site to another. If travelers navigate by the stars, for example, the stars are their wayfinding tools. Maps and compasses are also wayfinding tools.
All models are wayfinding tools. A model is a set of symbols and text used to make a complex concept easier to grasp. The world around us is full of obstacles that can overwhelm our senses and make it very challenging to focus only on the relevant information needed to make intelligent decisions. A map helps a visitor navigate a city. An organization chart helps an employee understand reporting relationships. A blueprint helps an architect communicate building plans. The map, organization chart, and blueprint are all types of models that represent a filtered, simplified view of something complex, with the goal of improving a wayfinding experience by helping people understand part of the real world.
It would probably have taken me hours of trial and error to reach my destination in France, whereas that simple map the gas station attendant drew provided me with an almost instantaneous broad understanding of how to reach my destination. A model makes use of standard symbols that allow one to grasp the content quickly. In the map he drew for me, the attendant used lines to symbolize streets, and circles to symbolize roundabouts. His skillful use of those symbols helped me visualize the streets and roundabouts.
Data Model Explained
When I was in college, the term ‘information overload’ was used to mean that my brain had reached the maximum number of words spoken by the professor, appearing on her flipcharts, and in the page of notes in front of me, that it could handle. It was time for a stroll around campus, a game of tennis, or a couple of quarters in Space Invaders to get my mind recharged and ready for more. Today however, it seems that we are creating and receiving more and more information, and taking fewer and fewer breaks. I have heard it quoted several times that the amount of information in the world is increasing by over 60% per year! I shudder to myself, wondering what very small portion of all of this information we really, truly understand.
Luckily, there is a tool that can help simplify all of this information - the data model. A data model is a wayfinding tool for both business and IT professionals, which uses a set of symbols and text to precisely explain a subset of real information to improve communication within the organization and thereby lead to a more flexible and stable application environment. A line represents a motorway on a map of France. A box with the word ‘Customer’ within it represents the concept of a real Customer such as Bob, IBM, or Walmart on a data model.
Our broad definition of a data model as “a set of symbols and text which precisely explain a subset of real information” encompasses models in many different forms. Data models can look like the box and line drawings which are the subject of this book, or they can take other forms, such as Unified Modeling Language (UML) Class Diagrams, spreadsheets, or State Transition Diagrams. All of these models are wayfinding tools designed with the single purpose of simplifying complex information in our real world
Fun with Ice Cream
Perhaps the most common form of data model we work with on a daily basis is the spreadsheet. A spreadsheet is a representation of a paper worksheet containing a grid defined by rows and columns, where each cell in the grid can contain text or numbers. The columns often contain different types of information. For example, I recently returned from a trip to Rome and I loved their ice cream (gelato). Upon entering a gelato store, you will see several spreadsheets. One example is shown in Table 1.1, which is a list of ice cream flavors. Table 1.2 contains the ice cream sizes along with prices.
Table 1.1 Sample ice cream flavors
Banana
Cappuccino
Chocolate
Chocolate Chip
Coffee
Kiwi
Marshmallow
Pistachio
Strawberry
Vanilla
Table 1.2 Ice cream sizes with prices
1 Scoop 1.75
2 Scoops 2.25
3 Scoops 2.60
This is a data model because it is a set of symbols (in this case, text) that are used to describe something real in our world (in this case, the yummy ice cream flavors along with prices). Guess how many scoops of chocolate gelato I purchased?