建立模型关系时，Related Field的查找无效

Question

我试图使关系遍历不同的模型，但遇到了以下错误：

django.core.exceptions.FieldError: Related Field got invalid lookup: occupational_group

以下是我的型号：

class LoanApplication(models.Model, TimeStampedModel):
loan_taker = models.ForeignKey(
CustomerProfile, on_delete=models.PROTECT, null=True, blank=True,
verbose_name=_('Customer Profile'), related_name='loan_entries')

class CustomerProfile(models.Model, TimeStampedModel):
is_copy_component = models.BooleanField(
_('Is copy component'), default=False)
cooperation_partner = models.ForeignKey(
EmailUser, on_delete=models.PROTECT, null=True, blank=True,
verbose_name=_('Jurisdiction'), related_name='partner_user_profile')
user = models.OneToOneField(
EmailUser, on_delete=models.PROTECT, null=True, blank=True,
verbose_name=_('User'), related_name='user_profile')
approval_inquiry_sent_at = models.DateTimeField(
_('Approval inquiry sent at'), null=True, blank=True)
email_content_customer = models.FileField(
_('Content of the customer email'), upload_to="customer-emails/",
blank=True)
approved_at = models.DateTimeField(
_('Approved at'), null=True, blank=True)

class CustomerProfilePerson(models.Model, TimeStampedModel):

person = models.ForeignKey(
Person, on_delete=models.CASCADE,
verbose_name=_('Person'), related_name='customer_profile_relation')
customer_profile = models.ForeignKey(
CustomerProfile, on_delete=models.CASCADE,
verbose_name=_('Customer Profile'), related_name='persons')

class Person(models.Model, TimeStampedModel):
occupational_group = models.CharField(
_('Occupational group'), max_length=16, blank=True,
choices=OCCUPATIONAL_GROUP_CHOICES)

我试图用occupation group的关系过滤LoanApplication模型，下面是职业组的列表：

OCCUPATIONAL_GROUP_CHOICES = (
('pharmacist', _('Pharmacist')),
('architect', _('Architect')),
('doctor', _('Doctor')),
('consulting_eng', _('Consulting engineer')),
('notary', _('Notary')),
('psychotherapist', _('Psychotherapist')),
('lawyer', _('Lawyer')),
('tax_consultant', _('Tax Consultant')),
('vet', _('Vet')),
('sworn_auditor', _('Sworn auditor')),
('surveyor', _('Surveyor')),
('auditor', _('Auditor')),
('dentist', _('Dentist')),
('other', _('Other')),
)

所以这是我下面的查询，但失败了：

LoanApplication.objects.filter(loan_taker__persons__person__occupational_group__in: ['pharmacist'])

我得到了这个例外：

django.core.exceptions.FieldError: Related Field got invalid lookup: occupational_group

Answer 1

您用冒号(:(而不是等号(=(将参数传递给函数，因此您应该使用进行筛选

LoanApplication.objects.filter(
loan_taker__persons__person__occupational_group__in=['pharmacist']
)

由于您只匹配一个有一个项目的列表，因此您可以将其替换为：

LoanApplication.objects.filter(
loan_taker__persons__person__occupational_group='pharmacist'
)