Leonardo's blog

Object Pascal compilers offers a wide range of classes and components that allows you to connect to different databases, ranging from BDE to open source components. But many of them only works in Delphi or only in FreePascal, turning very dificult to develop cross platform database applications.

One of the most known data access components is Zeos Lib, a heavy weight component library that allows you to acces a lot of database backends like MySql, PostGreSQL, Oracle, MsSql Server, Interbase and others. It's free, open source and works on Delphi, Kylix and FreePascal. You can get more information and download from http://sourceforge.net/projects/zeoslib, also, if you want to install it in Lazarus must read this http://wiki.lazarus.freepascal.org/index.php/Zeos_tutorial.

If you (like me) like smaller and faster programs, i'll recommend a small library called LibSQL. Just like Zeos, this library allows access to different databases, but allows you to use driver you want, making the executable many times smaller than Zeos. If you want to download it, go to http://sourceforge.net/projects/libsql

If you know different cross platform libraries or components like Zeos or LibSQL, please comment on them.