On 25/04/2013 15:04, Michael Bayer wrote:
the columns come out in order because they have a "creation order" counter
running that tracks the order in which each object was created. There's nothing like
that built into @declared_attr,
I think declared_attr is a bit of a red herring here, it's the creation
order coming from the mixin class being processed before the class using
it. I don't think that's avoidable ;-)
I guess if it produces an object reference we could add the creation counter to
it as well.
I think we'd need some way to re-order columns as part of some
post-metaclass thing. Sounds like a lot of work for not much gain. If it
really annoys me, I can always fiddle with the postgres internals way of
re-ordering columns in a table...
cheers,
Chris
On Apr 25, 2013, at 4:57 AM, Chris Withers<ch...@simplistix.co.uk> wrote:
Hi All,
I didn't see anything in the code that could help here (except maybe
__declare_last__, but that looks like something else) but thought I'd ask in
case I'm missing something...
So, some of my mixins include columns that logically come later than the
columns defined in the class using the mixin, eg:
class Temporal(object):
value_from = Column(DateTime(), nullable=False, index=True)
value_to = Column(DateTime(), nullable=False, index=True)
@declared_attr
def value_on(cls, timestamp=None):
if timestamp is None:
timestamp=datetime.now()
return ((cls.value_from<= timestamp)&
(cls.value_to> timestamp))
class Observation(Temporal, Base):
instrument_id = Column(String(10), ForeignKey('instrument.id'),
primary_key=True)
source = Column(String(10), primary_key=True)
type = Column(String(10), index=True)
value = Column(Numeric())
The value_from and value_to columns belong at the end of the definition, but:
-> \d observation
Table "public.observation"
Column | Type | Modifiers
---------------+-----------------------------+-----------
value_from | timestamp without time zone | not null
value_to | timestamp without time zone | not null
instrument_id | character varying(10) | not null
source | character varying(10) | not null
type | character varying(10) |
value | numeric |
Not a biggie, but curious if there's a way to get them to the end...
cheers,
Chris
--
Simplistix - Content Management, Batch Processing& Python Consulting
- http://www.simplistix.co.uk
--
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
For more options, visit https://groups.google.com/groups/opt_out.
--
Simplistix - Content Management, Batch Processing & Python Consulting
- http://www.simplistix.co.uk
--
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
For more options, visit https://groups.google.com/groups/opt_out.
