PHP Cookbook

Chapter 10. Database Access

Introduction

Databases are central to many web applications. A database can hold almost any collection of information you may want to search and update, such as a user list, a product catalog, or recent headlines. One reason why PHP is such a great web programming language is its extensive database support. PHP can interact with (at last count) 17 different databases, some relational and some not. The relational databases it can talk to are DB++, FrontBase, Informix, Interbase, Ingres II, Microsoft SQL Server, mSQL, MySQL, Oracle, Ovrimos SQL Server, PostgreSQL, SESAM, and Sybase. The nonrelational databases it can talk to are dBase, filePro, HyperWave, and the DBM family of flat-file databases. It also has ODBC support, so even if your favorite database isn’t in the list, as long as it supports ODBC, you can use it with PHP.

If your data storage needs are simple and you don’t need to serve many users, you may be able to use a plaintext file as a makeshift database. This is discussed in Recipe 10.2. Text files require no special database software but are appropriate only for lightly used, basic applications. A text file can’t handle structured data well; if your data changes a lot, it’s inefficient to store it in a plain file instead of a database.

DBM flat-file databases, discussed in Recipe 10.3, offer more robustness and efficiency than flat files but still limit the structure of your data to key/value pairs. They scale better than plaintext ...