Programming Visual Basic 2008

Chapter 4. Designing the Database

Data. Databases. It just kind of makes sense. If you have data, you need to put it somewhere. And what better place to put it than in a “data” base?

Just to make sure I had all the “bases” covered, I did a quick search on the Internet for a useful definition. What a shock. According to virtually every web site I found, a database is “a collection of data organized for easy retrieval by a computer.” With a definition like that, pretty much everything I put on my system is stored in a database. All my disk files are organized for easy access. My saved emails can be sorted by subject or date received or sender, so they must be in a database, too. Even this document can be searched and sorted in any manner I wish. Is it a database?

Relational Databases

Perhaps that definition is too broad. These days, when we think of “database,” it’s generally a relational database system. Such databases are built on the “relational model” designed by Edgar Codd of IBM. In 1970, he issued “A Relational Model of Data for Large Shared Data Banks,” the seminal paper on relational modeling, and later expanded on the basic concepts with C. J. Date, another “real programmer.” Upon reading that 1970 paper—and if you have a free afternoon, you would really benefit from spending time with your family or friends rather than reading that paper—you will enter a world of n-tuples, domains, and expressible sets. Fortunately, you don’t need to know anything about these terms to use ...