Michael Bayer wrote:
>
>> Which docs do I need to understand what all this means and where do I
>> find them?
>
> that would be here:
> http://www.sqlalchemy.org/docs/05/mappers.html?highlight=large%20collections#working-with-large-collections
Cool, so my model now looks like:
Base = declarative_base(engine=engine)
class Unit(Base):
__tablename__ = 'units'
id = Column(Integer,primary_key=True)
name = Column(String)
class Record(Base):
__tablename__ = 'records'
timestamp = Column(DateTime,primary_key=True)
unit_id = Column(Integer,ForeignKey('units.id'),primary_key=True)
unit = relation('Unit',
backref=backref('records',
order_by=timestamp.desc(),
lazy='dynamic'))
is_on = Column(Boolean)
mode = Column(Integer)
error = Column(Integer)
set = Column(Integer)
measured = Column(Integer)
...and I can get the latest record for a unit with:
unit = session.query(Unit).filter(Unit.id==3).first()
unit.records.first()
...which is excellent :-)
Now, how would I get all the records for a particular timeframe for a
unit, ordered oldest to newest? (eg: all the records for today, or all
the records for 08:00-12:00 today)
This needs to be as efficient as possible as each unit generates one
record per minute, so once this has been up for a year, we're talking
about 260,000-ish records, of which I only want, say 1,440 for the whole
day or 240 for 08:00-12:00.
cheers,
Chris
--
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