SQLAlchemy: get Model from table name. This may imply appending some function to a metaclass constructor as far as I can see

Question

I want to make a function that, given the name of a table, returns the model with that tablename. Eg:

class Model(Base):     __tablename__ = 'table'     ...a bunch of Columns  def getModelFromTableName(tablename):    ...something magical 

so getModelFromTableName('table') should return the Model class.

My aim is to use the function in a simple form generator I'm making since FormAlchemy does not work with python3.2 and I want it to handle foreign keys nicely.

Can anyone give me any pointers on how to get getModelFromTableName to work?

Here's one idea I have (it might be totally wrong, I haven't worked with meta classes before...)

What if I were to make my Model classes inherit from Base as well as some other class (TableReg) and have the class meta of TableReg store Model.tablename in some global dictionary or Singleton.

I realise this could be totally off because Base's metaclass does some very important and totally nifty stuff that I don't want to break, but I assume there has to be a way for me to append a little bit of constructor code to the meta class of my models. Or I don't understand.

Answer 1

Inspired by Eevee's comment:

def get_class_by_tablename(tablename):   """Return class reference mapped to table.    :param tablename: String with name of table.   :return: Class reference or None.   """   for c in Base._decl_class_registry.values():     if hasattr(c, '__tablename__') and c.__tablename__ == tablename:       return c 

Answer 2

Beware the OrangeTux answer does not take schemas in account. If you have table homonyms in different schemas use:

def get_class_by_tablename(table_fullname):   """Return class reference mapped to table.    :param table_fullname: String with fullname of table.   :return: Class reference or None.   """   for c in Base._decl_class_registry.values():     if hasattr(c, '__table__') and c.__table__.fullname == table_fullname:       return c 

fullname is a Table attribute see:

github.com/sqlalchemy/sqlalchemy/blob/master/lib/sqlalchemy/sql/schema.py#L530-L532