django.db.utils.ProgrammingError：运算符不存在：字符更改日期

Question

I am querying from a PostGre db in my Django project.

Below is my code.

flight_schedule_detail_instance = FlightScheduleDetail.objects.filter
            schedule_id=FlightSchedule.objects.filter(schedule_id=instance.schedule_id),
            flight_date=str(tomorrow_date)
            )

I need to filter all the instances which has a particular schedule_id and a flight_date . This works in my localhost. I am using sqlite in my localhost code. The server uses PostGre db. How do I query to get my desired results?

Also, flight_date in my FlightScheduleDetail model is a DateField . And my schedule_id is a Foriegn key to another model which is a CharField in that model.

I also tried without having a str wrapper to my tomorrow_date variable which is a date object.

My models.py :

class FlightScheduleDetail(models.Model):
    flight_date = models.DateField(max_length=30, null=False, blank=False)
    schedule_id = models.ForeignKey(FlightSchedule, null=False, related_name="schedule_details", blank=False)
    route_id = models.CharField(max_length=150, null=False, blank=False, unique=True)
    flight_status = models.ForeignKey(Status, null=True, default=1)

    def __unicode__(self):
        return u'%s' % self.route_id

    class Meta:
        verbose_name_plural = "flights Schedule Details"


class FlightSchedule(models.Model):
    tail_number = models.ForeignKey(TailNumber, null=False, blank=False)
    schedule_id = models.CharField(max_length=40, null=False, blank=False, unique=True)
    flight_group_code = models.ForeignKey(FlightGroup, null=False, blank=False)
    minLength = MinLengthValidator(limit_value=7)
    binary = RegexValidator(r'^[0-1]*$', 'Only 0s and 1s are allowed.')
    scheduled_days = models.CharField(max_length=7, validators=[binary, minLength], null=True, blank=True,
                                      default="1111111")
    origin_port_code = models.ForeignKey(Port, null=False, related_name="Origin", blank=False)
    destination_port_code = models.ForeignKey(Port, null=False, related_name="Destination", blank=False)
    flight_departure_time = models.TimeField()
    start_date = models.DateField()
    end_date = models.DateField()

    def __unicode__(self):
        return u'%s' % self.schedule_id

    class Meta:
        verbose_name_plural = "flights Schedule"

and I am calculating my tomorrow_date as follows :

tomorrow_date = datetime.date.today() + datetime.timedelta(days=1)

Answer 1

This is a classic example of why you should use the same database in development and production. Sqlite does not have a concept of types. You can declare field types but they are not strictly followed. So you can easily insert text data into Date fields. Postgresql on the other hand is very strict about types.

Updating my answer based on updates to the question.

I am not quite sure, if you need that elaborate query. You have an instance of a FlightSchedule and that instance will give you direct access to all the related FilightScheduleDetail instances. you can just filter on it like this

instance.flightscheduledetail_set.filter(flight_date=tommorow_date)

If you continue to have the error, it can only mean that there is a missig migration somewhere.