I am using Django Rest Framework and I have this query in raw SQL but I want to do it in the Django ORM instead.
I have tried using the different Django tools but so far it has not given me the expected result.
select tt.id, tt.team_id, tt.team_role_id, tt.user_id from task_teammember tt
inner join task_projectteam tp on tp.team_id = tt.team_id
where tp.project_id = 1
models
class TeamMember(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
team = models.ForeignKey(Team, on_delete=models.CASCADE)
team_role = models.ForeignKey(TeamRole,on_delete=models.CASCADE)
state = models.IntegerField(default=1)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(default=None, null=True)
class ProjectTeam(models.Model):
project = models.ForeignKey(Project, on_delete=models.CASCADE, blank=True, null=True)
team = models.ForeignKey(Team, on_delete=models.CASCADE, blank=True, null=True)
state = models.IntegerField(default=1)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(default=None, null=True)
If you have a project object already then this should get you what I believe you want. Your TeamMember model has access to Team, which links to ProjectTeam, and to Project - the double-underscore accessor navigates through the relationships.
TeamMember.objects.filter(team__projectteam__project=project)
I would advise to span a ManyToManyField over the ProjectTeam, this will make queries simpler:
from django.conf import settings
class TeamMember(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
updated_at = models.DateTimeField(auto_now=True)
# …
class Team(models.Model):
projects = models.ManyToManyField(Project, through='ProjectTeam')
# …
class ProjectTeam(models.Model):
# …
updated_at = models.DateTimeField(auto_now=True)
Then you can easily filter with:
TeamMember.objects.filter(team__projects=project_id)
Note: It is normally better to make use of the settings.AUTH_USER_MODEL [Django-doc] to refer to the user model, than to use the User model [Django-doc] directly. For more information you can see the referencing the User model section of the documentation.
Note: Django's DateTimeField [Django-doc]
has a auto_now=… parameter [Django-doc]
to work with timestamps. This will automatically assign the current datetime
when updating the object, and mark it as non-editable (editable=False), such
that it does not appear in ModelForms by default.
I think it's goes like:
TeamMember.objects.filter(team__projectteam__project__id=1)
Django orm allow reverse foreginkey lookup
Related
I have 3 django tables connected like this:
Is there anyway to make a query for table Table that will get id_equip from table equip?
models.py
class Vendor(models.Model):
vendor_name = models.CharField(max_length=50)
def __str__(self):
return self.vendor_name
class Equipment(models.Model):
equipment_name = models.CharField(max_length=50)
id_vendor = models.ForeignKey(Vendor, on_delete=models.CASCADE, default=None)
def __str__(self):
return self.equipment_name
class Table(models.Model):
table_name = models.CharField(max_length=100)
id_vend = models.ForeignKey(Vendor, on_delete=models.CASCADE, default=None)
id_equip = models.ManyToManyField(Equipment)
This part of the django docs is relevant and helpful, I definitely recommend your review at least that section and ideally the whole page.
Your models are already denormalized as evidenced by Table.id_equip which relates to Equipment so you could do:
table = Table.objects.get(SOME_FILTER)
equipment_ids = list(table.id_equip.all().values_list('id', flat=True))
If you wanted to go through the vendor I'd suggest:
table = Table.objects.get(SOME_FILTER)
equipment_ids = list(Equipment.objects.filter(vendor_set__table_set=table).values_list('id', flat=True))
I would recommend that you don't name your relationship fields with id_. With an ORM, these fields should represent the instances of the Model they are mapping to. For example:
class Table(models.Model):
name = models.CharField(max_length=100)
vendor = models.ForeignKey(Vendor, on_delete=models.CASCADE, default=None)
equipment = models.ManyToManyField(Equipment)
If you're trying to create the model on top of an existing table, you can make use of the db_column parameter when defining the field.
vendor = models.ForeignKey(Vendor, on_delete=models.CASCADE, default=None, db_column="id_vend")
In the past, I think there was a model atrtibute named unique_for to define a foreignKey but I can't find it anymore.
Suppose a model named Recommendation. A User can recommend many websites but only one by domain. So, I wanted to set a unique_for('user', 'recommendation.domain') or something like like this.
What's the current way to do it ?
Recommendation Model:
class Recommendation(models.Model):
is_recommended = models.BooleanField(default=True)
what = models.ForeignKey('Website', on_delete=models.CASCADE)
who = models.OneToOneField(User, on_delete=models.CASCADE)
title = models.CharField(max_length=255)
why = models.CharField(max_length=255, null=True, blank=True)
when = models.DateTimeField(auto_now_add=True)
class Meta:
ordering = ["-when"]
User Model is the Django built in.
Thanks
I've found my answser.
The attribute is unique_together and not unique_for
I'm working to remove an existing GenericForeignKey relationship from some models. Id like to change it to the Reformatted Model below. Does migrations provide a way to convert the existing content_type and object_ids to the respective new ForeignKey's? (to keep existing data). Basically brand new at programming, so pardon me if I'm asking a stupid question.
class Donation(models.Model):
amount_id = models.CharField(max_length=12, unique=True, editable=False)
date_issued=models.DateField(auto_now_add=True)
description=models.TextField(blank=True, null=True)
content_type = models.ForeignKey(ContentType)
object_id = models.PositiveIntegerField()
content_object = generic.GenericForeignKey('content_type','object_id')
class Individual(BaseModel):
first_name = models.CharField(max_length=50)
middle_name = models.CharField(max_length=50, blank=True,
null=True)
last_name = models.CharField(max_length=50)
suffix = models.CharField(max_length=50, blank=True, null=True)
contributor = generic.GenericRelation(Donation, related_query_name='individual')
class Organization(models.Model):
name = models.CharField(max_length=100)
contributor = generic.GenericRelation(Donation, related_query_name='organization')
Reformatted Model
class Donation(models.Model):
amount_id = models.CharField(max_length=12, unique=True, editable=False)
date_issued=models.DateField(auto_now_add=True)
description=models.TextField(blank=True, null=True)
contributor_group = models.ForeignKey(Organization, null=True, blank=True, on_delete=models.CASCADE)
contributor_individual = models.ForeignKey(Individual, null=True, blank=True, on_delete=models
Based on your model definition of Donation Model, one of fields contributor_group , contributor_model will always be Null post migration.
I hope you have taken that into you consideration.
Just to be safe Do this in two phases.
1. Keep the content_type and object_id and add the two new fields.
2. Next step remove the generic fields post data population.
There are two ways to populate those new fields
Django migrations provides you a way to populate new fields with values during the migrations. You can look it up. I haven't done that before either.
For more control and some learning as well. You can populate that via scripting as well. You can setup django-extensions module in your project. And write a script to do that population for you as well. A sample script would look like.
from myproject.models import Donation, Individual, Organization
from django.contrib.contenttypes.models import ContentType
def run():
organization_content_type = ContentType.objects.get_for_model(Organization)
individual_content_type = ContentType.obejcts.get_for_model(Individual)
donations = Donation.objects.all()
for donation in donations:
if donation.content_type_id == organization_content_type.id:
donation.contributor_group = donation.object_id
elif donation.content_type_id == individual_content_type.id:
donation.contributor_individual = donation.object_id
else:
print "Can't identify content type for donation id {}".format(donation.id)
donation.save()
Check the values are correct and then remove the generic fields.
Facing some issues with formatting here.
I am trying to export all my database with a prefetch_related but I only get data from the main model.
My models:
class GvtCompoModel(models.Model):
gvtCompo= models.CharField(max_length=1000, blank=False, null=False)
...
class ActsIdsModel(models.Model):
year = models.IntegerField(max_length=4, blank=False, null=False)
...
class RespProposModel(models.Model):
respPropos=models.CharField(max_length=50, unique=True)
nationResp = models.ForeignKey('NationRespModel', blank=True, null=True, default=None)
nationalPartyResp = models.ForeignKey('NationalPartyRespModel', blank=True, null=True, default=None)
euGroupResp = models.ForeignKey('EUGroupRespModel', blank=True, null=True, default=None)
class ActsInfoModel(models.Model):
#id of the act
actId = models.OneToOneField(ActsIdsModel, primary_key=True)
respProposId1=models.ForeignKey('RespProposModel', related_name='respProposId1', blank=True, null=True, default=None)
respProposId2=models.ForeignKey('RespProposModel', related_name='respProposId2', blank=True, null=True, default=None)
respProposId3=models.ForeignKey('RespProposModel', related_name='respProposId3', blank=True, null=True, default=None)
gvtCompo= models.ManyToManyField(GvtCompoModel)
My view:
dumpDB=ActsInfoModel.objects.all().prefetch_related("actId", "respProposId1", "respProposId2", "respProposId3", "gvtCompo")
for act in dumpDB.values():
for field in act:
print "dumpDB field", field
When I display "field", I see the fields from ActsInfoModel ONLY, the starting model. Is it normal?
You haven't understood the arguments to prefetch_related. It's not a list of fields, but a list of models.
(Note that your field naming convention is also very misleading - respProposId1 and actId are not IDs, but actual instances of the models. Django has created an underlying field in each case by appending _id, so the db columns are respProposId1_id and actId_id. You should just call the fields resp_propos1 and resp_propos2 - also note that normal style is lower_case_with_underscore, not capWords.)
It is normal, that you are seeing fields from ActsInfoModel only. You can access related models via dot notation, like:
acts = ActsInfoModel.objects.all().prefetch_related("actId", "respProposId1", "respProposId2", "respProposId3", "gvtCompo")
for act in acts:
print act.respProposId1.respPropos
Related models are already prefetched, so it won't produce any additional queries. FYI, quote from docs:
Returns a QuerySet that will automatically retrieve, in a single
batch, related objects for each of the specified lookups.
This is are my models i want to relate. i want for collection to appear in the form of occurrence.
class Collection(models.Model):
id = models.AutoField(primary_key=True, null=True)
code = models.CharField(max_length=100, null=True, blank=True)
address = models.CharField(max_length=100, null=True, blank=True)
collection_name = models.CharField(max_length=100)
def __unicode__(self):
return self.collection_name
class Meta:
db_table = u'collection'
ordering = ('collection_name',)
class Occurrence(models.Model):
id = models.AutoField(primary_key=True, null=True)
reference = models.IntegerField(null=True, blank=True, editable=False)
collection = models.ForeignKey(Collection, null=True, blank=True, unique=True),
modified = models.DateTimeField(null=True, blank=True, auto_now=True)
class Meta:
db_table = u'occurrence'
Every time i go to check the Occurrence object i get this error
TemplateSyntaxError at /admin/hotiapp/occurrence/
Caught an exception while rendering: column occurrence.collection_id does not exist
LINE 1: ...LECT "occurrence"."id", "occurrence"."reference", "occurrenc..
And every time i try to add a new occurrence object i get this error
ProgrammingError at /admin/hotiapp/occurrence/add/
column occurrence.collection_id does not exist
LINE 1: SELECT (1) AS "a" FROM "occurrence" WHERE "occurrence"."coll...
What am i doing wrong? or how does ForeignKey works?
The problem is that you have not updated your database table definition since adding the ForeignKey. syncdb doesn't do this for you, as the documentation clearly states. You need to update the SQL manually, or use a tool like South.
Are you sure you mean
collection = models.ForeignKey(Collection, null=True, blank=True, unique=True),
Nullable and Unique? This may not be possible in some databases.
Generally, the unique constraint doesn't seem to make much sense here.
Are you trying to force a 1-to-1 relationship? Use the OneToOneField. http://docs.djangoproject.com/en/1.1/ref/models/fields/#django.db.models.OneToOneField