[SQLObject] Re: Strange bug with SQLObject 0.6

[Carlos R. <car...@gm...>]

I've found my 'bug', and it hasn't nothing to do with naming
conventions. It was a mistake of mine: my one-to-many relationship
used a different column name from the default one, and I was not aware
that in this case I had to supply a joinedColumn parameter (in fact,
another user pointed it out to me, but I misunderstood his point, and
assumed that I just had to upgrade my SQLObject installation).

Regarding this problem, I have a suggestion: add a remark on the
"One-to-Many Relationships" section of the documentation. The relevant
information does exist but it's buried down in the MultipleJoin
reference; so when I replayed the example provided in the tutorial
section it worked, but I was not aware of the option, until I read the
reference. For example, something like this:

http://www.sqlobject.org/docs/SQLObject.html:
"""
We get the backreference with addresses = MultipleJoin('Address').
When we access a person's addresses attribute, we will get back a list
of all the Address objects associated with that person. An example:

p = Person(firstName='John', lastName='Doe')
print p.addresses
#>> []
a1 = Address(street='123', city='Smallsville',
                 state='IL', zip='50484', person=p)
print [a.street for a in p.addresses]
#>> ['123']

In this case, the relationship between the 'Person' entity and the
'Address.person' ForeignKey() column is detected and created with no
need for any extra information -- the name is mapped automatically.
However, if the name of the ForeignKey() column is different from the
entity name which it relates with, a joinedColumn argument will be
required. For example:

<...> 
"""

I found my mistake only after realizing that the join method had no
other way to find the joined-to column :-) But it's easy to overlook
it, because SQLObject abstracts very well from these 'implementation
details'. That's why I believe a comment early in the documentation
(or in a FAQ section) could be useful.

-- 
Carlos Ribeiro
Consultoria em Projetos
blog: http://rascunhosrotos.blogspot.com
blog: http://pythonnotes.blogspot.com
mail: car...@gm...
mail: car...@ya...