Pascal Data Objects provides a consistent interface to access databases. 

Currently, only the MySQL and Firebird databases are supported, but additional drivers can easily be added. As these drivers are developed, they will be made available. 

PDO is inspired by the PHP PDO extension, so people familiar with the PHP version will have no problem making the jump to the pascal version. This database interface is heavily modified derivative work of ZeosLib, so therefore it is still covered by the LGPL license. This code was created by John Marino, Director at synsport.com, for use with their fantasy league manager software. 

It is compatible with Borland Delphi (tested on version 7) and Free Pascal Compiler 2.0. For FPC, the code has been tested on Windows XP and FreeBSD 4.10, 6.0, and 6.1 Unix.

Страница проекта на Source Forge

Честно скажу, сам я не пробовал устанавливать и изучать. Даже из описания не смог понять для чего это нужно   

Это PHP-like библиотека для доступа к базам данных.
Удобно для тех, кто работает с одной и той же базой их Delphi/FPC и PHP.