[SQLObject] Re: SQLObject inheritance patch 2

[Oleg B. <ph...@ph...>]

On Thu, Feb 12, 2004 at 08:51:06AM -0500, Daniel Savard wrote:
>    I sent you a little test (your test with very smalls modifications) 
> and the complete SQLObject.py file patched with my patch.

   Your SQLObject.py is exactly like my - byte to byte. No difference.

>    It is not needed to create and drop table each time.  Only to be 
> sure they are created.
>    Can you try it and tell me if its works now ?

   Your test works ok. But the following program does not:

import SQLObject
db_conn = SQLObject.PostgresConnection(db = 'test')

class Woman(SQLObject.SQLObject):
   _inheritable = 1
   _connection = db_conn
   name = SQLObject.StringCol()

class Wilma(Woman):
   smile = SQLObject.IntCol()

woman = Woman(1)
print woman # prints <Wilma 1 childName=None smile=1>, ok
print woman.smile # => 1
print woman.name

   Output:

<Wilma 1 childName=None smile=1>
1
Traceback (most recent call last):
  File "w2", line 15, in ?
    print woman.name
  File "<string>", line 1, in <lambda>
AttributeError: 'Wilma' object has no attribute '_parent'

>    As for assigning the _parent variable only in new, it is needed 
> because we must link to the true instance of the parent class at this 
> time to be able to get the good properties.

   Aha, I see the problem now. Your patch works only when a program
creates a new object. Than the class got _parent attribute. If the
program does not calls new() - oops, attribute error.

Oleg.
-- 
     Oleg Broytmann            http://phd.pp.ru/            ph...@ph...
           Programmers don't die, they just GOSUB without RETURN.