On 21.10.2008, at 20:22, Michael Bayer wrote:
>
> There's a couple of odd practices here, and removing each one
> individually may narrow down where things are going wrong.
>
> 1. What happens if you use the correct class, patient.op_ci_implant(),
> instead of "chartitem" which does not match the given type of
> "op_ci_implant" ?
> 2. Why does the primaryjoin condition for "chart" include a foreign
> key value of 0 ? Note that SQLA probably cannot handle primary key
> values of "0" at this time.
> 3. Does the chartitem object attached to testpat.chart[0] have a
> primary key or was that not flushed properly either ? What happens
> if you query for the parent chartItem directly and do not include
> "patient" in the operation ? Simplifying each step and asserting
> sanity on each one is the key to isolating where something is going
> wrong.
Thank you very much for answering Micheal
As for 1.
It produces the same error if I use the patient.op_ci_implant. I
forgot to put it back in, after I experimented with chartItem.
2.
I use patient_chart.c.Parent==0 to exclude all non "root" items from
patient.chart[]. But this does not seem to be the error. The simpler
test file I created does not include it and still the same problem.
But later on more to this topic.
3.
testpat.chart[0] has the correct foreign key.
I have reimplemented the problem in a simpler, easier to understand
source file. I have appended it to this mail. I really hope that
somebody can help. This is driving me nuts!
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from sqlalchemy import *
from sqlalchemy.orm import *
engine = create_engine('sqlite:///:memory:', echo=False)
Session = sessionmaker(bind=engine)
session = Session()
metadata = MetaData()
# this table contains the base data for a patient, like his name, phone number ...
patient_table = Table('patient', metadata,
Column('patID', Integer, primary_key=True, nullable = False),
Column('name', String),
)
# Stores data like which operations have been performed on a patient or which exams have been performed ...
patientChart_table = Table('patientChart', metadata,
Column('id', Integer, primary_key=True, nullable = False),
Column('parent', Integer, ForeignKey('patientChart.id')),
Column('type', String),
Column('patID', Integer, ForeignKey('patient.patID'), nullable = False),
)
# contains the info about examinations
examination_table = Table('exams', metadata,
Column('id', Integer, ForeignKey('patientChart.id'), primary_key=True, nullable = False),
Column('date', DateTime),
)
metadata.create_all(engine)
class patient(object):
class chartItem(object):
pass
class exam(chartItem):
pass
mapper(patient.chartItem, patientChart_table, polymorphic_on=patientChart_table.c.type, polymorphic_identity='type',
properties={
'id': patientChart_table.c.id,
'patID': patientChart_table.c.patID,
'parent': patientChart_table.c.parent,
'type': patientChart_table.c.type,
'children': relation(patient.chartItem)
})
mapper(patient.exam, examination_table, inherits=patient.chartItem, polymorphic_identity='exam',
properties={
'id': examination_table.c.id,
'date': examination_table.c.date,
})
mapper(patient, patient_table, properties={
'id': patient_table.c.patID,
'name': patient_table.c.name,
'chart': relation(patient.chartItem)
})
testpat = patient()
testpat.name = "Test Patient"
session.add(testpat)
testpat.chart.append(patient.exam())
testpat.chart.append(patient.exam())
session.commit()
print testpat.chart[0].id, testpat.chart[0].patID
print testpat.chart[1].id, testpat.chart[1].patID
testpat.chart[0].children.append(patient.exam())
session.commit()
