Till Klampaeckel has posted the second part of his look at migrating your application away from the relational world of MySQL and into the document-oriented toolset CouchDB has to offer. You can find part one here.
In part I, I introduced CouchDB by explaining its basics. I continued by showing a simple request to create a document using curl (on the shell) and expanded how the same request could be written in PHP (using ext/curl) - or in HTTP_Request2 or with phpillow. Part II will focus on the most basic operations and help you build a small wrapper for CouchDB. The code will be available on Github.
He briefly covers some of the features of the database, the Futon software to interact with it and some of the basics on the usual CRUD (Create, Read, Update, Delete) operations. The sample code shows how to add a new document into the database, pull it back out (with a get() call) and delete the document from the database completely. The source for the example is here.