I have this 2 models:
class BuildingStructure(models.Model):
bldg_name = models.CharField(max_length=100)
height = models.FloatField()
code = models.CharField(max_length=25)
block_name = models.CharField(max_length=75)
bldg_type = models.CharField(max_length=50)
brgy_locat = models.CharField(max_length=50)
geom = models.MultiPointField(srid=32651, null=True, blank=True)
objects = models.GeoManager()
def __unicode__(self):
return self.bldg_name
class FloodHazard(models.Model):
gridcode = models.IntegerField()
hazard = models.CharField(max_length=6)
date_field = models.CharField(max_length=50)
geom = models.MultiPolygonField(srid=32651, null=True, blank=True)
objects = models.GeoManager()
def __unicode__(self):
return self.hazard
hazard field in the model has the following values: 'High', 'Medium', 'Low'.
I wanted to create a report in a table format(HTML) like this:
I tried this so far:
getgeom = FloodHazard.objects.get(id=512).geom
getgeom_medium = FloodHazard.objects.get(id=620).geom
getgeom_low = FloodHazard.objects.get(id=638).geom
response_data = {}
response_data["medium"] = list(BuildingStructure.objects.filter(geom__intersects=getgeom_medium).values( 'brgy_locat').annotate(countmedium=Count('brgy_locat')))
response_data["high"] = list(BuildingStructure.objects.filter(geom__intersects=getgeom).values('brgy_locat').annotate( counthigh=Count('brgy_locat')))
response_data["low"] = list(BuildingStructure.objects.filter(geom__intersects=getgeom_low).values('brgy_locat').annotate( countlow=Count('brgy_locat')))
result = {}
for category in response_data.values():
for element in category:
key = element.pop('brgy_locat')
if key not in result:
result[key] = {"loc":key}
result[key].update(element)
json_result = result.values()
return HttpResponse(list(json.dumps(json_result)), content_type='application/json')
The above code works fine as I am able to get my intended output. But as you examine it, I tried one id in each hazard type. So my problem now is to use filter to get all the ids and used it as reference in my GeoQuerySet. Any help will be appreciated. I'm trying to pass the data as JSON in my template because I'm using datatables.
This is how I get all the ids for e.g. hazard type "high"
reference = FloodHazard.objects.filter(hazard='High')
ids = reference.values_list('id', flat=True)
for id in ids:
#something has to be done here...
Related
I have a model Field that has a OneToMany connections with TreeSensor and WeatherStation model. Im trying to pass over the queries of each treesensor/weatherstation model that match the id of each different field but get a Field 'id' expected a number but got <built-in function id>. .How do i fix that? Maybe change something on the filter ?
class Field(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE, blank=True, null=True, default=None)
friendly_name = models.CharField(max_length=24, blank=True)
soil_type = models.CharField(max_length=24, choices=SOIL_TYPES, blank=True)
cultivation = models.CharField(max_length=128, choices=CULTIVATIONS, blank=True)
kml = models.FileField(upload_to = user_directory_path_kml, null=True, blank=True)
class TreeSensor(models.Model):
field = models.ForeignKey(Field, on_delete=models.CASCADE)
...
class WeatherStation(models.Model):
field = models.ForeignKey(Field, on_delete=models.CASCADE)
...
view
def map(request):
field_list = models.Field.objects.filter(user = request.user)
tree_sensors = models.TreeSensor.objects.filter(field__pk = id)
weather_stations = models.WeatherStation.objects.filter(field__pk = id)
context = {
"title": "Map",
"field_list": field_list,
"tree_sensors": tree_sensors,
"weather_stations" : weather_stations,
}
template = 'agriculture/map.html'
return render(request, template, context)
On your view you are filtering some field called field by id, which is not defined nowehere....
You have a queryset of Fields, so probably you should do something like this:
def map(request):
field_list = models.Field.objects.filter(user = request.user).values_list('id', flat=True)
tree_sensors = models.TreeSensor.objects.filter(field__id__in = field_list)
weather_stations = models.WeatherStation.objects.filter(field__id__in = field_list)
#Walucas your approach was correct it was kinda different though . It works out like this :
view
def map(request):
field_list = models.Field.objects.filter(user = request.user)
tree_sensors = models.TreeSensor.objects.filter(field_id__in = field_list.values_list('id',flat=True))
weather_stations = models.WeatherStation.objects.filter(field_id__in = field_list.values_list('id',flat=True))
context = {
"title": "Map",
"field_list": field_list,
"tree_sensors": tree_sensors,
"weather_stations" : weather_stations,
}
template = 'agriculture/map.html'
return render(request, template, context)
I want to create a new object in ModelB when specific condition are met in ModelA. I am new to Django so that I am unable to figure out how exactly I can achieve this.
For example I have two models(Product and ProductVariant), when specific condition on ProductVariant is met then I want to calculate new object value in Product model.
My Product model is like this:
PRODUCT_TYPE = (
('s', 'simple'),
('v', 'varaible')
)
class Products(models.Model):
name = models.CharField(max_length=250,null=True, blank=True,)
slug = models.SlugField(max_length=200, unique=True,null=True)
short_description = HTMLField()
description = HTMLField()
category = models.ForeignKey(Categories, related_name="products",on_delete=models.SET_NULL,null=True,blank=True,)
brand = models.ForeignKey(Brands,on_delete=models.CASCADE, default=None, null=True, blank=True,)
warranty_support = HTMLField()
product_type = models.CharField(choices=PRODUCT_TYPE, default='simple', max_length=50)
And my Product Attribute Model is like this:
class ProductVariant(models.Model):
product = models.ForeignKey(Products,on_delete=models.CASCADE)
variant = models.ForeignKey(ProductAttribute,on_delete=models.CASCADE, null = True, default=None)
managed_stock = models.IntegerField(choices=STOCK_MANAGED, default=0)
stock = models.IntegerField(default=None)
stock_threshold = models.IntegerField()
price = models.DecimalField(max_digits=10, decimal_places=2)
sku = models.CharField(max_length= 250, default=None)
sale_price = models.DecimalField(max_digits=10, decimal_places=2)
sale_start_date=models.DateField(auto_now_add=False, auto_now=False, default=None)
sale_end_date=models.DateField(auto_now_add=False, auto_now=False,default=None)
I am trying to create regular_price and sale_price on Product model if product_type is variable and if sale_end_date is greater than today. I want to set the price from the variant which has the lowest price.
I tried doing like this on Product model:
def clean(self):
if self.product_type == 'varaible' and ProductVariant.objects.filter(product=self, variant_count__gt = 1):
self.min_price = ProductVariant.objects.filter(product=self).Min('price')
self.max_price = ProductVariant.objects.filter(product=self).Max('price')
but I am not able to achieve what I want,
How can I do this?
After some research and analysis I found solution to my problem, I am posting the solution here so that someone with similar problem could be benefited.
#property
def get_price(self):
result = dict()
variants = ProductVariant.objects.filter(product=self)
count = variants.count()
if count > 1:
min_variant = variants.order_by('price').first()
max_variant = variants.order_by('-price').first()
result['min_price'] = min_variant.price
result['max_price'] = max_variant.price
elif count == 1:
variant = variants.first()
if variant.sale_price:
result['price'] = variant.price
result['sale_price'] = variant.sale_price
sale_variant = variants.order_by('sale_price').first()
result['lowest_sale_price'] = sale_variant.sale_price
result['regular_price'] = sale_variant.price
today = datetime.date.today()
if variant.sale_start_date <= today and variant.sale_end_date >= today:
result['sale_end_date'] = variant.sale_end_date
else:
result['price'] = variant.price
I want to select elements from my Django database on two conditions - whether the boolean value "used" is true and whether or not the "dateUsed" is within the last 20 days. However, my current filter statement is returning an empty QuerySet, even though there should be elements that meet both conditions. Am I filtering the elements correctly? I've attached the code that filters the elements, the definitions of my models, as well as the block of code that changes the value of "used" once the model elements have been displayed on my site.
Filter:
def pastSongs(request):
window = datetime.now().date() - timedelta(days=20)
songHistory = Song.objects.filter(used = True).filter(dateUsed__gt = window)
ent = {}
ent["ent"] = songHistory
return render(request, 'rollingStone/songs.html',ent)
Models:
class Song(models.Model):
rank = models.IntegerField()
artist = models.CharField(max_length=100)
title = models.CharField(max_length=100)
cover = models.URLField()
writers = models.CharField(max_length=100)
producers = models.CharField(max_length=100)
releaseInfo = models.CharField(max_length=100)
description = models.TextField(max_length=3000)
used = models.BooleanField(default=False)
dateUsed = models.DateField(auto_now=True)
Changing "used" field:
def reload():
# Change status of old song/album to used, and save the date that it was used
if entry["status"] == "filled":
currentSong = Songs.objects.get(entry["songEnt"].name)
currentAlbum = Albums.objects.get(entry["albumEnt"].name)
currentSong.dateUsed = datetime.now().date() - timedelta(days=1)
currentAlbum.dateUsed = datetime.now().date() - timedelta(days=1)
currentSong.used = True
currentAlbum.used = True
currentSong.save()
currentAlbum.save()
Your problem might be that you are doing something weird with the window date...
Other than that you could write a manager for your model:
managers.py:
from django.db.models import QuerySet, Q
SongQuerySet(QuerySet):
def used_and_in_time_window(time_window):
return self.filter(Q(used=True) & Q(dateUsed__gte=time_window))
models.py :
class Song(models.Model):
rank = models.IntegerField()
artist = models.CharField(max_length=100)
title = models.CharField(max_length=100)
cover = models.URLField()
writers = models.CharField(max_length=100)
producers = models.CharField(max_length=100)
releaseInfo = models.CharField(max_length=100)
description = models.TextField(max_length=3000)
used = models.BooleanField(default=False)
dateUsed = models.DateField(auto_now=True)
objects = SongQuerySet.as_manager()
usage:
def pastSongs(request):
time_window = datetime.date(datetime.now()) - timedelta(days=20)
songHistory = Song.objects.used_and_in_time_window(time_window)
ent = {}
ent["ent"] = songHistory
return render(request, 'rollingStone/songs.html',ent)
Also you might wanna pack the time delta value to an environment variable so you don't have to make a commit if you wanna change that in the future.
I am trying to write a year level filter for my student profile list, however, the query returns an empty [].
This is my Attendance model, manager and custom queryset:
class AttendanceQuerySet(models.QuerySet):
def get_yearlevel(self, yearlevel):
return self.filter(BCEID__YearLevel = yearlevel)
class AttendanceManager(models.Manager):
def get_queryset(self):
return AttendanceQuerySet(self.model, using=self._db)
def get_yearlevel(self, yearlevel):
return self.get_queryset().get_yearlevel(yearlevel)
class Attendance(models.Model):
BCEID = models.OneToOneField(StudentProfile,primary_key=True,on_delete=models.CASCADE)
AttendanceRate = models.CharField(max_length=10)
objects = AttendanceManager()
def __unicode__(self):
return self.BCEID
StudentProfile model:
class StudentProfile(models.Model):
RelatedPersonName = models.CharField(max_length=10)
RelatedPersonFirstName = models.CharField(max_length=30)
RelatedPersonFamName = models.CharField(max_length=30)
StudentLegalName = models.CharField(max_length=30)
StudentFamName = models.CharField(max_length=30)
Email = models.CharField(max_length=130)
Street1 = models.TextField(max_length=30)
Suburb = models.CharField(max_length=30)
State = models.CharField(max_length=5)
PostCode = models.CharField(max_length=6)
StudentLegalName = models.CharField(max_length=30)
StudentFamName = models.CharField(max_length=30)
StudentNo = models.CharField(primary_key=True,max_length=10)
Class = models.CharField(max_length=6)
YearLevel = models.CharField(max_length=10)
objects = StudentProfileManager()
def __unicode__(self):
return self.StudentNo
and AttendanceListView (views.py)
class AttendanceListView(ListView):
model = Attendance
queryset = Attendance.objects.get_yearlevel("Year 8")
I manually queried the database to check if there were errors in my code, and got the same result: an empty array [].
SQL:
SELECT "student_attendance"."BCEID_id",
"student_attendance"."AttendanceRate"
FROM "student_attendance"
INNER JOIN "student_studentprofile"
ON ("student_attendance"."BCEID_id" = "student_studentprofile"."StudentNo")
WHERE "student_studentprofile"."YearLevel" = 'Year 8'
Please let me know what I am doing wrong here.
How can I pass the foreign key values from my model to my serialised json object?
Now I have this three models,
class Fleet(models.Model):
fleet_id = models.IntegerField('Id flota', primary_key=True, unique=True)
fleet_name = models.CharField('Nombre flota', max_length=20, unique=True)
def __str__(self):
return self.fleet_name + ' ' + str(self.fleet_id)
class Device(models.Model):
dev_eui = models.CharField(max_length=16, primary_key=True, unique=True)
producer = models.CharField(max_length=20)
model = models.CharField(max_length=20)
dev_name = models.CharField(max_length=20, unique=True)
fleet_id = models.ForeignKey(Fleet, on_delete=models.CASCADE)
def __str__(self):
return self.dev_eui
class DevData(models.Model):
data_uuid = models.UUIDField(primary_key=True, default=uuid.uuid1, editable=False)
frequency = models.IntegerField()
data_1 = models.FloatField()
data_2 = models.FloatField(null=True, blank=True)
dev_eui = models.ForeignKey(Device, on_delete=models.CASCADE) #hay que saber porque añade _id
def __str__(self):
return self.dev_eui
And what I'm doing is call my view function in my JS code to obtain some data like this.
def getData(request):
ctx = {}
if request.method == 'POST':
select = int(request.POST['Select'])
data = DevData.objects.order_by('dev_eui','-data_timestamp').distinct('dev_eui')
nodes = Device.objects.all()
fleets = Fleet.objects.all()
data = loads(serializers.serialize('json', data))
nodes = loads(serializers.serialize('json', nodes))
fleets = loads(serializers.serialize('json', fleets))
ctx = {'Data':data, 'Nodes':nodes, 'Fleets':fleets}
return JsonResponse(ctx)
And inside my js file I filter it with some if else conditionals.
This works well, but I'm sure I can do it directly in my view but I don't know how. How can I obtain just one JSON object with the three models information combined?
Thank you very much!!
You can write a custom serializer like this:
from django.core.serializers.json import Serializer
class CustomSerializer(Serializer):
def end_object(self, obj):
for field in self.selected_fields:
if field == 'pk':
continue
elif field in self._current.keys():
continue
else:
try:
if '__' in field:
fields = field.split('__')
value = obj
for f in fields:
value = getattr(value, f)
if value != obj and isinstance(value, JSON_ALLOWED_OBJECTS) or value == None:
self._current[field] = value
except AttributeError:
pass
super(CustomSerializer, self).end_object(obj)
Then use it like this
serializers = CustomSerializer()
queryset = DevData.objects.all()
data = serializers.serialize(queryset, fields=('data_uuid', 'dev_eui__dev_eui', 'dev_eui__fleet_id__fleet_name'))
I have wrote an article regarding serializing nested data here. You can check that out as well.