Core PHP Programming, Third Edition

1.3. Interfaces to External Systems

Originally, PHP was famous for interfacing with many different database systems, but it also has support for other external systems. Support comes in the form of modules called extensions. They either compile directly into PHP or are loaded dynamically. New extensions are added to the PHP project regularly. The extensions expose groups of functions for using these external systems. As mentioned, some of these are databases. PHP offers functions for talking natively with most popular database systems, and it provides access to ODBC drivers. Other extensions give you the ability to send messages using a particular network protocol, such as LDAP or IMAP. These functions are described in detail in Part II. Because ...