Upgrading to PHP 5

Chapter 4. SQLite

Substituting text files for a database is like cutting a fish with a hammer. You might get it to work, but it’s going to be a really messy process. When your application needs a server-side storage mechanism but you can’t rely upon the presence of a specific database, turn to SQLite. It correctly handles locking and concurrent accesses, the two big headaches with home-brewed flat files.

Since the SQLite database is bundled with PHP 5, now every PHP 5 script can read, write, and search data using SQL. SQLite differs from most databases because it is not a separate application. Instead, SQLite is an extension that reads from and writes to regular files on the hard drive. Any PHP users who have permission to manipulate files can use SQLite to edit a database, just like they can use GD to edit images.

Although the name SQLite hints at a less than full-featured product, SQLite actually supports almost all of SQL92, the SQL standard specification. Besides the usual INSERTs and SELECTs, with SQLite you can also use transactions, query using subselects, define your own functions, and invoke triggers.

SQLite actually performs most actions more quickly than many other popular databases. In particular, SQLite excels at SELECTing data. If your application does an initial (or periodic) data INSERT and then reads many times from the database, SQLite is an excellent choice. The PHP web site uses SQLite to handle some forms of searches.

Unfortunately, SQLite has some downsides. Specifically, ...