In the last few months, I've heard a person say this multiple times

"business runs on de-normalized data"

The context of this statement has always been the discussion of database design and implementation... and I continue to wonder where this person's experience is coming from, to make such a statement. In my world - the business of developing software to run a business or automate a portion of a business - this is very far from the truth. My response to this statement is (and yes, you can quote me on this - please do)

Management reports on de-normalized data, but operations runs entirely on well-normalized data

I'm not going to make any ignorant or naive claims about de-normalized data having no place in business. There certainly is a lot of business value in de-normalized data. That's why we have data warehousing, OLAP cubes, and other reporting database structures (including Views, Stored Procedures, etc. that will de-normalize data for live reporting). When it comes to the day to day business, though - the people on the floor doing the low level business work - well normalized data is an absolute must.

From WikiPedia's entry on Database Normalization:

Database normalization, sometimes referred to as canonical synthesis, is a technique for designing relational database tables to minimize duplication of information and, in so doing, to safeguard the database against certain types of logical or structural problems, namely data anomalies. For example, when multiple instances of a given piece of information occur in a table, the possibility exists that these instances will not be kept consistent when the data within the table is updated, leading to a loss of data integrity. A table that is sufficiently normalized is less vulnerable to problems of this kind, because its structure reflects the basic assumptions for when multiple instances of the same information should be represented by a single instance only.

I'm certainly not a DBA and I'm not a real database guru. I do have more than 10 years experience working with various database systems (SQL Server, Access, Oracle, SQLite, MySQL, DB2/DB400, and XML & flat files , etc.) in various business scenarios (manufacturing, engineering, business process automation, e-commerce/e-business, enterprise integration, etc. etc.) and I have a pretty high opinion of my relational modeling capabilities ... and It evokes a sense of disbelief and shock when I see poorly normalized schema's or hear statements like this being made.

Please, please, PLEASE take the time to understand what well normalized database design is and why it's necessary for flexible, maintainable software.