Wiley Professional SQL Server 2000 Programming 978-0-7645-4379-1 User Manual
Product codes
978-0-7645-4379-1
Chapter 1
10
A Brief History of Databases
SQL Server is an RDBMS – or Relational Database Management System. RDBMS systems are at the
pinnacle of their popularity at the moment. Using an RDBMS as the basis for data storage is plainly "the
way it's done" for most applications nowadays – but it wasn't always this way.
pinnacle of their popularity at the moment. Using an RDBMS as the basis for data storage is plainly "the
way it's done" for most applications nowadays – but it wasn't always this way.
In this section, we're going to take a look back in time and examine some of the other databases used in
the past. We'll try not to dwell on this "Old News", but it's critical to understand where database
technology has come from if you want to understand where you're going today, and why.
the past. We'll try not to dwell on this "Old News", but it's critical to understand where database
technology has come from if you want to understand where you're going today, and why.
Types of Databases
Databases are not just limited to the computer-based systems that we typically think about when we
hear the term – they are much, much more. A database is really any collection of organized data. Even
Webster's dictionary puts a qualifier on any computer notion:
hear the term – they are much, much more. A database is really any collection of organized data. Even
Webster's dictionary puts a qualifier on any computer notion:
Database: A usually large collection of data organized especially for rapid search and retrieval (as
by a computer).
by a computer).
The file drawers in your office are really something of a database (that is, if they are better organized than
mine at home). In fact, databases have existed throughout most of the history of the "civilized" world,
going back to the days of the early philosophers and academics (Socrates, Aristotle, Hippocrates, etc.).
mine at home). In fact, databases have existed throughout most of the history of the "civilized" world,
going back to the days of the early philosophers and academics (Socrates, Aristotle, Hippocrates, etc.).
That being said, there's a reason why databases are so closely associated with computers. It's because,
for most database situations (virtually, but not quite, all of them), computers are simply the fastest and
most efficient way to store data. Indeed, the term database is thought to have originated from the
computing community in 1962 or so.
for most database situations (virtually, but not quite, all of them), computers are simply the fastest and
most efficient way to store data. Indeed, the term database is thought to have originated from the
computing community in 1962 or so.
Databases, then, fall into a number of common categories:
❑
Paper-based
: These, although often not thought of as databases, probably still make up the largest
proportion of databases in the world today. There are literally billions and billions of tons of paper
out there that are still meticulously organized, but haven't been anywhere near a computer.
out there that are still meticulously organized, but haven't been anywhere near a computer.
❑
Legacy mainframe
– often VSAM (Virtual Storage Access Method – common to IBM
mainframes) databases: Don't underestimate the number of legacy mainframes still out there,
and their importance. Connectivity to host systems and the vast amounts of data they still
contain is one of the major opportunity areas in database and systems development today.
There are still many situations where I recommend a host system solution rather than a client-
server or web-based model. It's worth noting though that I still believe in using a true RDBMS
– albeit one that's located on a host system.
and their importance. Connectivity to host systems and the vast amounts of data they still
contain is one of the major opportunity areas in database and systems development today.
There are still many situations where I recommend a host system solution rather than a client-
server or web-based model. It's worth noting though that I still believe in using a true RDBMS
– albeit one that's located on a host system.
❑
dBase
and other file-based databases: Typically, these include any of the older Indexed
Sequential
Access Method – or ISAM – databases. These normally use a separate file for each
table, but the ISAM name comes from the physical way the data is stored and accessed more
than anything else. Examples of ISAM databases that are still in widespread legacy use – and
even in some new developments in certain cases – include dBase, FoxPro, Excel, Paradox,
and Access. (Yes, Access is an ISAM with a relational feel and several relational features – it is
not, however, a true relational database system.) These systems had most of their heyday well
before RDBMS systems. (There is something of a paradox in this since RDBMS systems
appeared first.) These systems are still quite often great for small, stand-alone databases where
you will never have more than a small number of users accessing the data at a time.
than anything else. Examples of ISAM databases that are still in widespread legacy use – and
even in some new developments in certain cases – include dBase, FoxPro, Excel, Paradox,
and Access. (Yes, Access is an ISAM with a relational feel and several relational features – it is
not, however, a true relational database system.) These systems had most of their heyday well
before RDBMS systems. (There is something of a paradox in this since RDBMS systems
appeared first.) These systems are still quite often great for small, stand-alone databases where
you will never have more than a small number of users accessing the data at a time.