मुझे चलाने के लिए प्रयास करते समय, Django में एक निराशाजनक अड़चन त्रुटि हो रही है objects.all() के लिए Queryset वह prefetching है। एक मुद्दा है जहां कभी-कभी model._meta प्रतीत होता है कि तात्कालिकता के बीच फ़ील्ड गुम हो रही हैएक क्वेरीसेट की और इसके माध्यम से एक पुनरावृत्ति चल रहा है। यह लगभग है जैसे कि क्वेरीसेट की प्रीफेच वास्तव में ऑब्जेक्ट्स की सूची के पुनरावृत्ति के लिए समय में नहीं चलती है।
इस उदाहरण में, data.service_log बस कुछ प्रीफेच किए गए आइटमों के साथ एक क्वेरीसेट है servicelog। जब मैं खोल में क्वेरीसेट चलाता हूं, तो मैं सभी फ़ील्ड देख सकता हूं self.names_to_path(lookup_splitted, self.get_meta()) क्वेरीसेट पर विधि। वे सब वहाँ हैं, विशेष रूप से "servicelog।"
इस त्रुटि के लिए इस ट्रेसबैक पर ध्यान दें, यह कहता है"servicelog" एक उपलब्ध फ़ील्ड नहीं है, फिर भी यह इसे चुनने के लिए फ़ील्ड की सूची में सूचीबद्ध करता है। यह एक Django बग प्रतीत होता है, लेकिन मैं यह सुनिश्चित नहीं कर सकता क्योंकि मैं व्यवहार को समझाने या अलग नहीं कर सकता। मैं संभवतः इस त्रुटि को प्राप्त करने वाला एकमात्र व्यक्ति नहीं हो सकता। ऐसा लगता है django/db/models/sql/query.py में names_to_paths() तरीका। यहां "वह कोड है जो हल करने में विफल रहा है:
query.py names_to_paths():
field = None
try:
field = opts.get_field(name)
except FieldDoesNotExist:
if name in self.annotation_select:
field = self.annotation_select[name].output_field
if field is not None:
# Fields that contain one-to-many relations with a generic
# model (like a GenericForeignKey) cannot generate reverse
# relations and therefore cannot be used for reverse querying.
if field.is_relation and not field.related_model:
raise FieldError(
"Field %r does not generate an automatic reverse "
"relation and therefore cannot be used for reverse "
"querying. If it is a GenericForeignKey, consider "
"adding a GenericRelation." % name
)
try:
model = field.model._meta.concrete_model
except AttributeError:
model = None
else:
# We didn"t find the current field, so move position back
# one step.
pos -= 1
if pos == -1 or fail_on_missing:
field_names = list(get_field_names_from_opts(opts))
available = sorted(field_names + list(self.annotation_select))
raise FieldError("Cannot resolve keyword %r into field. "
"Choices are: %s" % (name, ", .join(available)))
break
field does not get set in the first try, then the condition statementअगर क्षेत्र कोई नहीं हैfails so we enter theअन्यblock. There theस्थितिgets reduced by one, but since this field is "servicelog" it is already at 0. However, when I try this in the shell, it always finds theखेतwithopts.get_field ( "servicelog") `। केवल WSGI और Apache2 से चलने पर यह विफलता होती है। दोबारा, यह हर समय नहीं है, जो परीक्षण करना बेहद मुश्किल बनाता है। मैं इस से परेशान हूं, और मुझे यकीन नहीं है कि सुराग कहां देखना है। कृपया अगर किसी के पास कोई विचार है कि क्या खोजा जाए, तो मैं बहुत सराहना करता हूं।
Traceback (most recent call last):
File "/var/www/fast/services/views/edit.py", line 12897, in service_log
for service in data.service_log:
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 258, in __iter__
self._fetch_all()
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 1076, in _fetch_all
self._prefetch_related_objects()
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 656, in _prefetch_related_objects
prefetch_related_objects(self._result_cache, self._prefetch_related_lookups)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 1457, in prefetch_related_objects
obj_list, additional_lookups = prefetch_one_level(obj_list, prefetcher, lookup, level)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 1556, in prefetch_one_level
prefetcher.get_prefetch_queryset(instances, lookup.get_current_queryset(level)))
File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/related_descriptors.py", line 802, in get_prefetch_queryset
queryset = queryset._next_is_sticky().filter(**query)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 790, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 808, in _filter_or_exclude
clone.query.add_q(Q(*args, **kwargs))
File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.py", line 1243, in add_q
clause, _ = self._add_q(q_object, self.used_aliases)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.py", line 1269, in _add_q
allow_joins=allow_joins, split_subq=split_subq,
File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.py", line 1149, in build_filter
lookups, parts, reffed_expression = self.solve_lookup_type(arg)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.py", line 1035, in solve_lookup_type
_, field, _, lookup_parts = self.names_to_path(lookup_splitted, self.get_meta())
File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.py", line 1330, in names_to_path
"Choices are: %s" % (name, ", ".join(available)))
FieldError: Cannot resolve keyword u"servicelog" into field. Choices are: additional_county_worker_notes, adoption_disrupted, adoption_first_name, adoption_last_name, adoption_middle_name, adoption_placement_date, adoption_placement_reason, adoption_placement_reason_id, adoption_placement_type, adoption_risk_level, adoption_risk_level_id, adoption_termination_date, adoption_termination_destination, adoption_termination_reason, adoption_termination_reason_id, adoptive_placement, agency, agency_id, all_items_outstanding, all_items_past_due, appeal_process_date, attached_file, attends_college, attorney_email_address, attorney_email_address_id, attorney_fax, attorney_fax_id, attorney_investigator_email_address, attorney_investigator_email_address_id, attorney_investigator_fax, attorney_investigator_fax_id, attorney_investigator_name, attorney_investigator_phone, attorney_investigator_phone_id, attorney_name, attorney_phone, attorney_phone_id, blood_related_to_applicants, blood_relationship, casa_email_address, casa_email_address_id, casa_fax, casa_fax_id, casa_name, casa_phone, casa_phone_id, certification_items_outstanding, certification_items_past_due, classification, classification_id, client, client_id, county_adoption_worker, county_adoption_worker_cell, county_adoption_worker_cell_id, county_adoption_worker_email_address, county_adoption_worker_email_address_id, county_adoption_worker_fax, county_adoption_worker_fax_id, county_adoption_worker_office, county_adoption_worker_office_id, county_adoption_worker_phone, county_adoption_worker_phone_id, county_adoption_worker_title, county_case_number, county_worker, county_worker_cell, county_worker_cell_id, county_worker_email_address, county_worker_email_address_id, county_worker_fax, county_worker_fax_id, county_worker_office, county_worker_office_id, county_worker_phone, county_worker_phone_id, county_worker_title, court, court_case_name, court_case_number, court_department, court_id, created, current_grade, date_identified_adoptive, date_placed_with_home, deleted, discharge_summary, eligibility_worker, eligibility_worker_email_address, eligibility_worker_email_address_id, eligibility_worker_phone, eligibility_worker_phone_id, emergency_placement, employed_80_hours, enable_discharge_summary, expected_type, expected_type_id, extended_family_contact_allowed, final_payment_amount, finalization_date, foreign_placement, hearing_36626_date, homestudy, id, incident_placement_1, incident_placement_2, incident_placement_3, incident_placement_4, individualized_plan_review, inhousemove, interpretive_summary, item_due, items_approved, items_pending, items_rejected, items_update_requested, la_county_id, medi_cal, medi_cal_eligibility_phone, medi_cal_eligibility_phone_id, medi_cal_eligibility_worker, medi_cal_id, modified, monthly_monitored_visit_hours, mother_child, move_in_type, move_out_type, new_protective_custody_petition, non_minor_dependent, non_truant, notes, number_of_files_required, other_school_contact, other_school_contact_first_name, other_school_contact_last_name, parent_payment_override_annually, parent_payment_override_daily, parent_payment_override_monthly, parental_contact_allowed, parental_group, parental_group_id, payment_amount, percent_certified, percent_items_complete, person_number, placement, placement_date, placement_id, placement_payment_override_annually, placement_payment_override_daily, placement_payment_override_monthly, placement_reason, placement_reason_details, placement_reason_id, placement_self, placer_shelter_bed, prior_placement, progress_summary, projected_adoption_36626_date, projected_adoption_finalization_date, projected_adoption_placement_date, recordreview, requires_educational_support, requires_mental_health_services, respite, school, school_different, school_id, school_liaison_email, school_liaison_first_name, school_liaison_last_name, school_liaison_phone, school_liaison_phone_extension, school_notes, serial_number, servicecontact_onbehalf, servicedeliverylog, servicelog, social_worker_at_termination, social_worker_at_termination_id, special_health_care_needs, state_case_number, teachers, termination_date, termination_destination, termination_reason, termination_reason_details, termination_reason_id, therapist, therapy_code, therapy_supervision_requirements, treatment_abilities, treatment_needs, treatment_preferences, treatment_strengths, treatmentneed, update_requested, update_requested_by, update_requested_by_id, update_requested_date, update_requested_note, updateable, use_number_required, uses_psychotropic_medication, visit_frequency_override, visit_frequency_override_id, visitation_restrictions, who_can_pickup_at_home, who_can_pickup_at_school, who_can_visit
अद्यतन - मॉडलों / अपमानजनक दृश्य कोड जोड़ना
models.py
class ParentalGroup(models.Model):
many fields...
class Placement(models.Model):
parental_group = models.ForeignKey(ParentalGroup, null=True, blank=True)
many more fields...
class ServiceLog(models.Model):
parental_group = models.ForeignKey(ParentalGroup, null=True, blank=True)
placement = models.ManyToManyField(Placement, blank=True)
many more fields...
views.py:
data.service_log = ServiceLog.objects.filter(
parental_group=data.pg,
).prefetch_related(
Prefetch(
"placement",
queryset=Placement.objects.all(),
to_attr="placements"
),
)
for service in data.service_log:
some code to generate data to pass to template...
return render_to_response(...)
उत्तर:
उत्तर № 1 के लिए 1मुझे गनिकोर्न / डीजेगो रनरवर पर Django 1.8.6 का उपयोग करने में भी एक ही समस्या थी। मैं शैल / नोटबुक पर्यावरण में त्रुटि को फिर से उत्पन्न करने में कामयाब नहीं हूं।
मैंने जोड़कर यादृच्छिक रूप से होने वाले फील्ड एरर को हल किया related_name को ManyToManyField। मैंनें इस्तेमाल किया एक मॉडल के माध्यम से हालांकि कईToManyField में।
आपके मामले में:
class ServiceLog(models.Model):
parental_group = models.ForeignKey(ParentalGroup, null=True, blank=True)
placement = models.ManyToManyField(Placement, blank=True, related_name="servicelog")
जनवरी