Question

我是django和python的新手。我正试图找出最好的（最高效的）查询方式。

这是我的模特：

class Immunization(models.Model):
    name = models.CharField(max_length=12, primary_key=True)
    verbose_name = models.CharField(max_length=80)
    desc = models.CharField(max_length=800)
    effective_duration = TimedeltaField()
    def __unicode__(self):
        return self.name

class Patient(models.Model):
    name = models.CharField(max_length=64)
    age = models.IntegerField()
    birthday = models.DateField()
    def __unicode__(self):
        return self.name

'''
    ImmunizationRecord is a specific date an immunization was administered to a given patient.
'''
class ImmunizationRecord(models.Model):
    patient = models.ForeignKey('Patient')
    immunization = models.ForeignKey('Immunization')
    date_administered = models.DateTimeField(auto_now_add=True)

我想要执行的查询是：

* 获取患者在过去的Immunizations.effective_duration中未收到的所有免疫接种。*

到目前为止，我正在做这样的事情：

def get_context_data(self, **kwargs):
    context = super(ProfileView, self).get_context_data(**kwargs)

    all = Immunization.objects.all()
    done = ImmunizationRecord.objects.filter(patient__name=self.request.user)

    for r in done:
        #TODO: add date check for expiry
        all = [s for s in all if r.immunization.name != s.name] 

    context['available_list'] = all
    return context

Answer 1

像这样的东西可能会改善一些事情。

Import numpy
Import datetime 
recent_immunizations = ImmunizationRecord.objects.filter(patient=request.user).order_by(date_administered).reverse()


output = []
for r in recent_immunization:
   if (datetime.datetime.today() - r.date_administered) > r.immunizations.effective_duration:
       output.append(r.immunization.name)

Waring此代码未经过测试！

Answer 2

获取患者过去未接受的所有免疫接种   Immunizations.effective_duration。

患者需要的所有疫苗接种。所以，如果他们接种疫苗20   几天前，又有效_duration = 19，那么他们已经过了1天   他们需要接种疫苗。

我们需要得到一个病人;然后他们收到所接种的任何免疫接种。那么我们需要知道从今天到每次免疫接种的日期有多大差异;如果差异小于有效天数;病人需要再次免疫接种。

import datetime

today = datetime.datetime.today()

p = Patient.objects.get(pk=1) # Get some patient
imm = ImmunizationRecord.objects.filter(patient=p) # This patient's record

still_needed = []

for record in imm:
   # How many days have passed since the immunization was administered?
   days_since = (today - record.date_administered).days

   if record.immunization.effective_duration < days_since:
      still_needed.append(record.immunization)

编写django ORM查询

2 个答案: