I guess my question is: How can I efficiently load Patient and its related
Encounters? I have tried various loading strategies of dynamic, joined (I
would think this would be the desired option), subquery, no load, etc., and
it these do not load. On the other hand, I can load Encounter just fine and
access an instance of the Patient object.
On Tuesday, May 31, 2016 at 11:20:37 AM UTC-5, Horcle wrote:
>
> I have the following two models:
>
> Class Encounter(Model):
> __tablename__ = 'cp_service'
> id = Column(Integer, primary_key=True, autoincrement=True)
> master_service_id = Column(String(255))
> admission_datetime = Column(DateTime)
> admission_provider_id = Column(String(255))
> admission_status = Column(String(255))
> age_at_visit = Column(String(255))
> attending_provider_id = Column(String(255))
> center = Column(String(255))
> department_name = Column(String(255))
> discharge_datetime = Column(DateTime)
> encounter_category = Column(String(255))
> encounter_class = Column(String(255))
> encounter_date = Column(DateTime)
> encounter_setting = Column(String(255))
> encounter_type = Column(String(255))
> primary_care_provider_id = Column(String(255))
> primary_service_yn = Column(String(255))
> provider_id = Column(String(255))
> serv_area_id_orig = Column(String(255))
> service_id = Column(Integer)
> patient_id = Column(Integer, ForeignKey('cp_patient.patient_id'))
> patient = relationship("Patient", backref=backref("patientEncounter"),
> lazy='eager', primaryjoin="Patient.patient_id==Encounter.patient_id")
>
> class Patient(Model):
> __tablename__ = 'cp_patient'
> id = Column(Integer, primary_key=True, autoincrement=True)
> first_name = Column(String(100))
> middle_name = Column(String(80))
> last_name = Column(String(80))
> sex = Column(String(80))
> race = Column(String(80))
> birth_date = Column(DateTime)
> ethnicity = Column(String(80))
> race = Column(String(80))
> patient_id = Column(Integer)
> mrn = Column(String(80))
> title = Column(String(80))
> suffix = Column(String(80))
> name_alias = Column(String(80))
> addr_1 = Column(String(80))
> addr_2 = Column(String(80))
> addr_3 = Column(String(80))
> city = Column(String(80))
> state = Column(String(80))
> country = Column(String(80))
> zip = Column(String(80))
> encounter = relationship("Encounter", backref=backref("Patient"), lazy
> ='dynamic', primaryjoin="Patient.patient_id==Encounter.patient_id")
>
>
> Where one patient can have many encounters.
>
> I am able to load the patent model fine in a scaffolded list when I
> comment out the encounter relationship in the last line (there are roughly
> 35K patients), but when I link it to Encounters (1.7 million), then I am
> running into major performance issues. I tried using lazy='dynamic', but
> got an error that:
> On relationship Encounter.patient, 'dynamic' loaders cannot be used with
> many-to-one/one-to-one relationships and/or uselist=False.
>
> What other options are there available to not load all the relations until
> needed?
>
> Thanks!
>
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