I usually work with SF2, and with Doctrine, Entities can be generated automatically and if you build the schema in a Soft like MySQL Workbench you can do Reverse Engineering
If you want to generate migration files from an existing mysql database you can use a Laravel package called XCMer / larry-four-generator. Apart from reverse engineering it has a bunch of other features.
Larry Four is a Laravel 4 package offering advanced model and migration generation functionality. Thanks to Larry you can quickly jot down the data scheme for your idea in an easy DSL and genereate migrations and models from it with just a single click. Larry can also analyse your existing data scheme and generate some magic for you too.
Try the original best master branch
https://github.com/XCMer/larry-four-generator/tree/master
or my Extended Models fork offering additional functionality
https://github.com/XCMer/larry-four-generator/tree/Gadoma-extendedmodels