Databases
   
    There were some changes in PHP 5 regarding databases (MySQL and SQLite).
   
   
    In PHP 5 the MySQL client libraries are not bundled, because of license
    problems and some others. For more information, read the FAQ entry.
   
   
    There is also a new extension, MySQLi (Improved
     MySQL), which is designed to work with MySQL 4.1 and above.
   
   
    Since PHP 5, the SQLite extension is
    built-in PHP. SQLite is an embeddable SQL database engine and is not a
    client library used to connect to a big database server (like MySQL or
    PostgreSQL). The SQLite library reads and writes directly to and from the
    database files on disk.