Introduction - Learning MySQL - page 5

sufficiently skilled programmer can look at the program code to find and perhaps
help in fixing problems.
MySQL actually has a dual-license approach: if you want to build your own prod-
uct around it, you pay MySQL AB a license fee. If you just want to use MySQL to
serve your own data, you don't have to pay the license fee. MySQL also offers
technical support, as do numerous other companies and consultants, some of them
probably near you.
Easy interface to other software
It is easy to use MySQL as part of a larger software system. For example, you can
write programs that can interact directly with a MySQL database. Most major
programming languages have libraries of functions for use with MySQL; these in-
clude C, PHP, Perl, Python, Ruby, and the Microsoft .NET languages. MySQL also
supports the Open Database Connectivity (ODBC) standard, making it accessible
even when MySQL-specific functionality isn't available.
Elements of MySQL and Its Environment
You need to master several skills to run a database system. In this section, we'll lay out
what goes into using MySQL and how we meet those needs in this topic.
A MySQL installation has two components: a server that manages the data, and cli-
ents that ask the server to do things with the data, such as change entries or provide
reports. The client that you'll probably use most often is the mysql “MySQL monitor”
program, provided by the MySQL AB company and available in most MySQL instal-
lations. This allows you to connect to a MySQL server and run SQL queries. Other
simple clients are included in a typical installation; for example, the mysqladmin program
is a client that allows you to perform various server administration tasks.
In fact, any program that knows how to talk to the MySQL server is a client; a program
for a web-based shopping site or an application to generate sales graphs for a marketing
team can both be clients. In Chapter 3, you'll learn to use the MySQL monitor client
to access the MySQL server. In Chapters 13 through 15, we'll look at how we can use
PHP to write our own custom clients that run on a web server to present a web frontend
to the database for this. We'll use the Apache web server ( http://httpd.apache.org ) .
Apache has a long history of reliable service and has been the most popular web server
in the world for over 10 years. The Apache web server—or “HTTP server”— project
is managed by the Apache Foundation ( http://www.apache.org ). Although the web
server and MySQL server are separate programs and can run on separate computers,
it's common to find small- to medium-scale implementations that have both running
on a single computer. In Chapters 16 through 18, we'll explore how the Perl program-
ming language can be used to build command-line and web interfaces to the MySQL
server.