Probably is pretty obvious for most of the advanced users, but when I started my experience with CakePHP I read a lot of configuring a database, but not multiple ones. There are articles how to use database for development and for production without changing anything but rewriting a function in DATABASE_CONFIG class.
These days we need to choose way of splitting the functionality and we have to decide: Shall we use different databases or shall we put a prefix for every table. So far we choose to use prefix, but I dig into this and I realized that every model could be attached to different database.
Here is the example how to do this: