How do create a custom database driver for CodeIgniter

How do you create a custom database driver to extend CodeIgniter's functionalities to other types of database systems? I'm using iRODS (www.irods.org). I ha开发者_高级运维ve a version of the site created using MySQL, but I want to be able to change the database backend with minimal changes. Is there an easy way to add this function, like how you can add a custom library in CI? I haven't been able to find any so far.

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I'm assuming you mean how do you create a custom Active Record driver for codeigniter? Otherwise I'm probably far off the mark here but:

There is no way I know of to simply extend or override the DB classes it is not a common thing. You can implement your own and patch up your CI config to use the new DB though.

Under system/database/drivers you find all the AR driver source. You would need to reimplement each function in each of the four files (may be able to skip on forge if you don't use it.)

I'd use the MySQL driver as a starting template as you mention you already use that, in which case you'll want to make sure all the features you use are re-implemented.

It sounds like a daunting task if you're not too experienced but I assure you the code is pretty simple.