SQL is the foundation for a growing range of open source relational
databases.
What is it?
Structured Query Language (SQL) is used to
interrogate and process data in a relational database. It was
developed by IBM for use on mainframes. SQL commands can work
interactively with a database or be embedded in a programming
language.
Relational database management systems (RDBMS) may be the next
field to go open source, with fully SQL-compliant Ansi-(American
National Standards Institute) approved open source databases
threatening to enter the mainstream. The three leading choices are
MySQL, PostgreSQL and Interbase.
In November 2000, US space agency Nasa replaced Oracle with MySQL
for a single non-critical application, the Nasa Acquisition
Internet Service (NAIS). But the news should alarm proprietary
database suppliers. The NAIS project leader reports an increase in
performance and no problems.
Nasa says the switch to open source was driven by cost.
Where did it originate?
SQL was developed by IBM in the
1970s. It is both an Ansi and ISO standard.
What makes it special?
SQL is the standard relational
database language. All relational database products - Oracle, DB2,
SQL Server and the rest - are based on it. SQL is usually used
within a programming language such as C, Cobol or Java.
"From one release to the next, Postgres [one of the organisations
offering open source RDBMS software] adds major features within a
matter of months, equivalent to upgrades that commercial software
companies take years to introduce," says Ned Lilly, vice-president
of open source development at software supplier Great Bridge.
"The unprecedented rate of revision stems from hundreds of loyal
and enthusiastic developers and users who brainstorm fixes and test
the latest tweaks, quickly reporting results from all kinds of
applications, configurations and platforms."
The simplicity of the open source licensing appeals to many
businesses resentful of the charges that the big suppliers
impose.
How difficult is it?
You can study SQL on its own - QA
Training runs a two-day course, for example - but you would
normally learn it as part of a supplier's database programming
course, such as Oracle's PL/SQL or Microsoft's Transact-SQL. With
SQL experience, you can train in an open source database in two to
three days.
Where is it used?
Like Linux, open source databases are
being introduced to larger organisations semi-officially by
techies, but there are some commercial users. Yahoo Finance uses
MySQL, and Motorola includes it in its developers' toolkit for the
Iden handset network system.
What does it run on?
Interbase comes from Borland,
which turned it from a proprietary to an open source RDBMS under
the Mozilla public license.
PostgreSQL was created by adding SQL to Postgres, which in turn was
evolved from Ingres by Michael Stonebraker at Berkeley.
MySQL has widespread backing. One distributor is NuSphere, owned by
the embedded database market leader, Progress Software. MySQL is
also included in Red Hat Linux 7.
Don't confuse
Open source with something you find in a
relish tray.
Few people know that
There is an open source site for
Oracle's PL/SQL, at www.plnet.sourceforge.net.
What's coming up?
Open source databases certified for
mainstream operating systems including Windows and Solaris.
Training
Although there are various SQL courses, a lot
of open source training, like the software, is available free
online.
www.postgresql.orgwww.mysql.comwww.inprise.com/interbase