Re: Custom joins on multiple columns with Q objects

[David Elias]

Another thing i can't resolve is construct contraints based in another
model other than the query original one.

With 0.96 i just passed the Options object - "q_filter.get_sql
(other_model._meta)".

Now I've tried:

class QJoin(object):
...
def add_to_query(self, query, used_aliases):
query.start_meta = self.model._meta
for child in self.where.children:
query.add_filter(child)
query.start_meta = None

But without success, the filters always apply to query.model._meta.

I've in the last days reading and analyzing the "model.sql" code but
probably i'm missing something.
--~--~-~--~~~---~--~~
You received this message because you are subscribed to the Google Groups 
"Django users" group.
To post to this group, send email to django-users@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at 
http://groups.google.com/group/django-users?hl=en
-~--~~~~--~~--~--~---

Re: Custom joins on multiple columns with Q objects

[David Elias]

Malcolm Tredinnick wrote:
> At some point in the future, multi-valued ON constraints might make an
> appearance (for example, multi-column primary key queries are possibly
> easier to write), but they might not, too. The slight preference for
> doing so at some point is that there are a couple of cases on some
> databases where join constraints are handled more efficiently than where
> constraints.
Well, that's what i am trying to do, only construct ON contraints for
composite primary keys, nothing else.

Anyway, thanks for your insightful reply.
--~--~-~--~~~---~--~~
You received this message because you are subscribed to the Google Groups 
"Django users" group.
To post to this group, send email to django-users@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at 
http://groups.google.com/group/django-users?hl=en
-~--~~~~--~~--~--~---

Custom joins on multiple columns with Q objects

[David Elias]

I'm using with Django 0.96 a custom Q object to make joins between
models, here's an example:

class Product(models.Model):
group = models.IntegerField() # primary key
code = models.CharField() # primary key
name = models.CharField()
...

class CartItem(models.Model):
product_group = models.IntegerField() # product foreign key
product_code = models.CharField() # product foreign key
quantity = models.IntegerField()
...


items = CartItem.objects.filter(
QJoin(Product, 'p', Q(group='product_group',
code='product_code'))).extra(
select={
'p.name': 'product__name'
})

for this to work i've translated this:
"Q(group='product_group', code='product_code')"

into this:
"ON (cartitem.product_group=p.group AND
cartitem.product_code=p.code)"

taking advantage of django.db.models.quey.Query._get_sql_clause
method:
if joins:
sql.append(" ".join(["%s %s %s ON %s" % (join_type, table,
alias, condition)
for (alias, (table, join_type, condition))
in joins.items()]))

Now on the new django.db.models.sql.query.BaseQuery i can add new
joins with the "join" method, but on "get_from_clause" the joins
construction does not allow me to construct a join on multiple
columns, here's the code from this method:
if join_type and not first:
result.append('%s %s%s ON (%s.%s = %s.%s)'
% (join_type, qn(name), alias_str, qn(lhs),
   qn2(lhs_col), qn(alias), qn2(col)))

The solution i can think of is to subclass de BaseQuery and overwrite
the "get_from_clause" method.
--~--~-~--~~~---~--~~
You received this message because you are subscribed to the Google Groups 
"Django users" group.
To post to this group, send email to django-users@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at 
http://groups.google.com/group/django-users?hl=en
-~--~~~~--~~--~--~---

Re: Cant access via fastcgi

[David Elias]

Manuel Meyer wrote:
> You don't have permission to access /home/myusername/public_html/
> ultimateWeimar/django.fcgi/ on this server.
In my case it was permissions, the .fcgi must be executable.

> IndexError: string index out of range
I was getting this error too because we must call it like this
django.fcgi/, note the trailing slash.


--~--~-~--~~~---~--~~
You received this message because you are subscribed to the Google Groups 
"Django users" group.
To post to this group, send email to django-users@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at 
http://groups.google.com/group/django-users
-~--~~~~--~~--~--~---