MySQL Workbench make entity-relation schema of your database. Here you can find some good info and here in wikipedia...
You can try File -> Export -> Forward Engineer SQL Create Script. Here you can generate the SQL Script corresponding to your EER diagram, and execute this script in your database engine.
I guess you mean the "C"-like symbol thy put on the lines used for expressing subtypes, right? This seems to stand for the set inclusion symbol (recall that A ⊂ B means that A is a subset of B) for indicating subclassing/subtyping/subseting.