Data Structure Modeling

This is a collection of information on Data Structure Modeling (some times called simply Data Modeling). This is an essential exercise to be carried out in any business BEFORE designing any computer system.

By John Owens • May 17th, 2010

Do We Need a Data Quality Profession?
In a recent article on Data Quality Arkady Maydanchik was suggesting that a key solution to the current data quality issues that plague business everywhere is the creation of a dedicated Data Quality profession.
In a reply to the article I suggested that, far from solving the problems, the creation of [...]

Postal addresses present data database developers with a constant challenge. Traditional approaches fail, either because they hard code in inadequate structures, or they provide the chaos of no structure at all. Generic data modeling can overcome both of these shortcomings and enable to expand and grow into multinational markets.

This is a very useful rule to use when building an Entity Relationship Diagram.

No crows were hurt during the construction of this diagram.

Codes are Not Identifiers
In my previous post on how unique keys cause duplication in databases I demonstrated that codes are not identifiers for data entities and, by extension, they cannot be unique identifiers (UIDs).
Why Do People Use Codes?
If codes are not identifiers how come they are used so extensively?  Because, when used properly, they are [...]

Data Quality Paradox
It is perhaps the greatest paradox of data quality that the primary cause of duplication of entries in any database is the mistaken use of unique keys as the unique identifiers of records.
The problem starts in the data modelling stage of analysis when data analysts use codes as the unique identifiers (UIDs) of [...]

I was recently discussing the the subject of modelling the structure of the extended family in a commercial environment. I had come across this when doing consultancy for a finance company located in London and Dublin.
They were loaning money for the purchase of motor vehicles and needed to know just how much exposure they [...]

I made this entry in response to a blog post I read about some anomalies in B2B (Business to Business) structures at Echoes in the Database.
That post essentially referred to what seemed like duplicate records in a table relating to an individual within a client company and was trying to decided whether or not they [...]

To most business people data modelling is a black art that is practiced by the company IT department. It brings no tangible business benefits and is solely designed to make mere mortals feel confused and inferior.  Sadly, many IT departments actually foster this view and, for those that do, the data modelling that they [...]

Proper business analysis can bring untold benefits to a business by bring power through simplicity and enabling quality information systems to be built to support and accelerate business success.
Bad business can bring untold misery to a business and can lock the staff inside complicated and inefficient procedures supported by poor information systems that severely restrict [...]

[I wrote the following comments in response to a blog that was advocating starting off by modeling the "as is" processes in the business as the starting point for business improvement.]
One of the major errors taken in business analysis and modeling is that of modeling the “As Is”, then the “To Be” and then trying [...]

Listen to John Owens introduce some of the basics of producing an information architecture for data management in this 1 minute MP3.

A newcomer to this subject asked me the question “Where do I start and what are the stages in Data Modeling?”.  Here, in brief, is the answer I gave.

The first step in data modeling is data analysis.  This means gathering information that will tell you what data entities are required by the business.
You then need to model [...]

Data is an invaluable asset. Not only is it essential for successfully supporting current operations but it will enable you to plan the future growth and success of your enterprise.
To this end Data Management is essential.
Effective Data Management needs an effective Data Architecture.
An effective Data Architecture can only be achieved by doing high quality [...]

In the building industry, before a building is ever erected you will have an architect’s plan defining in full each of its facets. You would then have wiring diagrams and plumbing diagrams. Last of all a decoration and furnishing plan. All of this before a brick is laid.
No builder would consider building a [...]

Before computerising any Business Functions it is essential to identify and model the data used or created by these Functions and its relationship to other data items (or data entities) within the business.  
This is where the Data Structure Model - often referred to as an Entity Relationship Diagram or ERD - is an indispensable model.
It is [...]