Code Igniter Database Library for Other Database

[eluser]Unknown[/eluser]
How is the query of Code Igniter Database Library work ? Is it supported for all other databases by just changing the line of dbdriver in database.php ? Or we have to do something more, for example change the query ? Refer to tech crunch, oracle is going to kill their world largest most used Open Source Mysql. http://techcrunch.com/2012/08/18/oracle-...rce-mysql/

i have to get prepared and ready to move all applications to another database, but I not sure how codeigniter database library work. Do i need to re-write all the code for query builder ? Couldn't find the specific line of description in their documentation. For example, i want to change all to postgresql ?