How do Rails associations look behind the scenes?

Can anyone point to some resource which shows how the tables are set up ( for MySQL for example ), on e开发者_StackOverflowach of the Rails associations ( one to one, one-to-many, many to many ). I understand how the associations work from a Rails point of view, but I don't understand how they work from the database's side.

http://edgeguides.rubyonrails.org/association_basics.html has images that detail the database columns.