On 7/23/15 2:18 PM, Rich Shepard wrote:
Originally posted here on June 4th, but no one responded. I'm now
back on
this project and this should be the last table I need to add to the
schema.
I would appreciate your review of the below class and whether it is
good to
go or needs your modifications.
Section 2.1.15 in the 1.0.8 manual describes building an association
table
for many-to-many relationships. My application has a table that
associates
multiple locations with multiple types of data collected. That is, each
location can have multiple types of data collected, and each data type
can
be collected at multiple locations. There are other attributes associated
with each row. Will the following table declaration work? Or, do I
separate
site and param into a separate table from the other columns?
conceptually not a big deal but API-wise has many mistakes. Sequences
don't work with unicode, there is no "value" parameter, the table has no
primary key.
----------
class Monitoring(Base):
__table_name__ = 'monitoring'
permit_nbr = Column(Unicode(24), ForeignKey('permits.nbr'))
permit = relationship("Permits", back_populates = 'locations')
data_type = Column(Unicode(16), CheckConstraint("data_type IN
('surface \
water', 'ground water', 'air', 'benthos', 'fish', 'microbes', \
'physical','weather')"))
site = Column(Unicode(12), Sequence('location_seq'), nullable =
False, \
unique = True, ForeignKen('locations.site_id'))
param = Column(Unicode(24), nullable = False, unique = True,
ForeignKey(\
'conditions.param_name'))
mcl = Column(Float)
monit_freq = Column(Unicode(12), value = 'Month', nullable = False, \
CheckConstraint("monitor_freq IN ('Hour','Shift','Day','Week','2x
month',\
'Month','Quarter','Semi-Annual','Annual')"))
rpt_freq = Column(Unicode(12), value = 'Month', nullable = False, \
CheckConstraint("rpt_freq IN ('Hour','Shift','Day','Week','2x
month',\
'Month','Quarter','Semi-Annual','Annual')"))
start_date = Column(Date, value = today, nullable = False)
end_date = Column(Date)
site = relationship("Locations", back_populates = 'monitoring')
param = relationship("Conditions", back_populates = 'monitoring')
---------
Rich
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