automating assignment of class variables

[Martin MOKREJŠ]

Hi,
 I need to build 3 classes for my work, but each have dozens or hundreds of
variables, self bound. I have about 250 columns in about 10 mysql tables.
I can squeeze everything into 10 classes, each representing single table.
I happily utilize the argument checks when a class is instantiated, so that
some variable must be non-empty. But, variables corresponding to ID's
(foreign keys) are allowed to be empty, as these objects I want to be able
to hold data to be saved, hence no requirements for ID's to be non-empty.

 Two classes define a two partly different combinations of MySQL tables
to be manipulated. The overlapping part in in superclass called "kommon".

I can save some typing using the superclass approach, but still find it
boring to do:

class kommon:
   def __init__(self):
       self.root = cElementTree.Element("xml dump")

   def set_submitter(self, submitter_object):
       # keep the reference to an external object hodling important data
       self.submitter = submitter_object

       # xml stuff to represent that data
       #
       submitter = cElementTree.SubElement(self.root, "submitter")
       first_name = cElementTree.SubElement(submitter, "first name")
       first_name.text = self.submitter.first_name
       last_name = cElementTree.SubElement(submitter, "last name")
       last_name.text = self.submitter.last_name
       email = cElementTree.SubElement(submitter, "email")
       email.text = self.submitter.email
       login = cElementTree.SubElement(submitter, "login")
       login.text = str(self.submitter.login)
       user_id = cElementTree.SubElement(submitter, "user_id")
       user_id.text = str(self.submitter.user_id)

   # more abstract and more multiplicated example
   def set_a(self, b_object, c_object, d_object):
       # a, b, c, d are objects, containing variable names corresponding to every
       #   column in MySQL table, where table a points to row in tables b, c, d
       # Actually, we must know the data held in b, c, d as the data are not yet flushed into
       # MySQL.
       self.b = b
       self.c = c
       self.d = d

       b_ = cElementTree.SubElement(self.root, "B")
       b_var1 = cElementTree.SubElement(b_, "VAR 1")
       b_var1.text = a.var1
       b_var2 = cElementTree.SubElement(b_, "VAR 2")
       b_var2.text = b.var2
       # ... many times the same logic

       c_ = cElementTree.SubElement(a_, "C")
       c_var1 = cElementTree.SubElement(c_, "VAR 1")
       c_var1.text = c.var1
       # ... many times the same logic
       
       d_ = cElementTree.SubElement(a_, "D")
       d_var1 = cElementTree.SubElement(d_, "VAR 1")
       d_var1.text = d.var1
       # ... many times the same logic

   def set_x(self, c_object, d_object):
       # damn, now I'm almost cut&pasting       
       c_ = cElementTree.SubElement(self.root, "C")
       c_var1 = cElementTree.SubElement(c_, "VAR 1")
       c_var1.text = c.var1
       # ... many times the same logic

       d_ = cElementTree.SubElement(c_, "D")
       d_var1 = cElementTree.SubElement(d_, "VAR 1")
       d_var1.text = d.var1
       # ... many times the same logic


The code outlined above has actually one serious error. I want to to self.a_ etc, not a_ as it gets
overwritten by successive instances of the same class. But am lazy to fix it now as I believe it's
anyway waste of time. ;)
Thansk for help!
Martin