if I have a model that has two model choice fields, is there a way to make the choice set of the second field dependent on what is chosen in the first. Example, if given the following code, the User chooses APPLE for the "company" field — can the code be configured such that the User is presented ONLY the APPLE DIV_CHOICES for his "division" field choices?
CMP_CHOICES ('Apple', 'Apple Computers'),
('MS', 'Microsoft Inc.'),
APPLE DIV_CHOICES ( 'Desktop', 'Desktop'),
( 'iOS', 'iOS'),
( 'AS', 'AppStore'),
MS DIV_CHOICES ( 'Windows', 'Windows'),
( 'Longhorn', 'Longhorn'),
( 'Mobile', 'Mobile'),
class Contact(models.Model)
first_name = models.CharField(max_length=64, …)
last_name = models.CharField(max_length=64, …)
company = models.CharField(max_length=100, choices=CMP_CHOICES)
division = models.CharField(max_length=100, choices=DIV_CHOICES)
....
No. Choices must be all choices that are ever possible. However, you may use JavaScript on your form to limit the choices based on the first selection, but not on the model itself.
There are lots of ways to go about this which will depend on whether you are using the django admin or your own custom code but out of the box it won't work - everything in the form is selectable by default.
You will end up do this at the form level and template level, not in the model. You could create a django form wizard to show the form in multiple stages. Alternatively you could use javascript to only show the APPLE/MS field after the CMP field has been selected. You could get fancier and do some ajax to dynamically load the APPLE/MS field after the CMP has been selected and validated.
Related
I wanted to know if there is a way to insert a search bar in the Django choices, that is instead of manually searching the various choices if it is possible to use a filter bar to search for our choice in Django Admin - Models.
Well I think django-filter library provide you with maybe good facilities for this purpose, I have briefly given you some examples from it's documentation below:
ChoiceFilter
This filter matches values in its choices argument. The choices must be explicitly passed when the filter is declared on the FilterSet.
class User(models.Model):
username = models.CharField(max_length=255)
first_name = SubCharField(max_length=100)
last_name = SubSubCharField(max_length=100)
status = models.IntegerField(choices=STATUS_CHOICES, default=0)
STATUS_CHOICES = (
(0, 'Regular'),
(1, 'Manager'),
(2, 'Admin'),
)
class F(FilterSet):
status = ChoiceFilter(choices=STATUS_CHOICES)
class Meta:
model = User
fields = ['status']
TypedChoiceFilter
The same as ChoiceFilter with the added possibility to convert value to match against. This could be done by using coerce parameter. An example use-case is limiting boolean choices to match against so only some predefined strings could be used as input of a boolean filter:
import django_filters
from distutils.util import strtobool
BOOLEAN_CHOICES = (('false', 'False'), ('true', 'True'),)
class YourFilterSet(django_filters.FilterSet):
...
flag = django_filters.TypedChoiceFilter(choices=BOOLEAN_CHOICES,
coerce=strtobool)
MultipleChoiceFilter
The same as ChoiceFilter except the user can select multiple choices and the filter will form the OR of these choices by default to match items. The filter will form the AND of the selected choices when the conjoined=True argument is passed to this class.
Multiple choices are represented in the query string by reusing the same key with different values (e.g. ‘’?status=Regular&status=Admin’’).
TypedMultipleChoiceFilter
Like MultipleChoiceFilter, but in addition accepts the coerce parameter, as in TypedChoiceFilter.
See also:
django-filter [Docs]
django-filter [Github]
I have a ModelForm class in which I set a couple of the fields as ChoiceField. For one of my views, I'd like to create a form from my ModelForm class that pulls from an instance of my model in the database (like so):
form = MyModel(instance=model_instance)
When I do this and then render the form in a template, I've noticed that most of the fields are pre-populated with values pulled from the model instance, which is what I want. However, this isn't the case for two ChoiceField fields. These render as drop-down select menus with no specific option selected.
What's strange is if I don't define those two fields as ChoiceField-type in my ModelForm class, they render as normal text input fields in HTML and pre-populate using the database values. But when I define them so they show up as select-option input fields in HTML, nothing is pre-selected. Can I change this so that the values from the database are pre-selected?
EDIT: As requested here is the code for my model and form:
class App(models.Model):
CODES = (
(u'a',u'annual'),
(u'm',u'monthly'),
(u'w',u'weekly')
)
code = models.CharField(max_length=1, choices=CODES)
start_time = models.TimeField(blank=True, null=True)
end_time = models.TimeField(blank=True, null=True)
class AppForm(ModelForm):
CODES = (
(u'',u'Please select code'),
(u'a',u'annual'),
(u'm',u'monthly'),
(u'w',u'weekly')
)
TIMES = (
(u'00:00',u'All Day'),
(u'12:00',u'Noon')
)
start_time = forms.ChoiceField(required=False, choices=TIMES)
end_time = forms.ChoiceField(required=False, choices=TIMES)
code = forms.ChoiceField(choices=CODES, label='Type')
class Meta:
model = App
Interestingly, code field has the model instance value preselected just fine when rendered as HTML. I wonder if having the choices argument in the model definition makes the difference here?
UPDATE: I just noticed that if I pull up an App instance in the python manage.py shell like so:
a = App.objects.get(id=16)
a.start_time
I get a value like datetime.time(12, 0). But in the Django admin, when I'm looking at all of the App instances, all of them show (None) under start_time and end_time. Why would that be?
In response to your update : your times strings match default time string HH:MM format. Just like a user would enter them from website manually 12:00. The values get parsed and turned into time at model save (at validating really).
And when you load model - then of course the initial values loaded from object match the field's (models.TimeField) type.
If you replace your TIMES with
(datetime.time(0,0),u'All Day'),
(datetime.time(12,0),u'Noon')
your troubles should be over.
Alan
I have a few models that look like this:
class System(models.Model):
'''Defines a system'''
system_desc = models.CharField('System Name', max_length=50)
class SystemGroup(models.Model):
'''Groups within a 'System' (ie. Customers, regions, divisions, etc. '''
group_desc = models.CharField('Group Name',max_length=25)
system = models.ForeignKey(System)
class QueryData(models.Model):
'''Queries related to a 'System' (ie. Active users against System1, Orders today in system2, etc. '''
qry_desc = models.CharField('Query Description', max_length=50)
system = models.ForeignKey(System)
class UserDashboard(models.Model):
'''User specific Dashboard '''
user = models.ForeignKey(User)
board_name = models.CharField('Dashboard Name', max_length=50)
class UserDashboardGroup(models.Model):
'''Groups on the dashboard (ie. 'System 1's Key Indicators', 'System 2's Hot Sheet', etc. '''
group_desc = models.CharField('Group Display Title', max_length=50)
user = models.ForeignKey(User)
dashboard = models.ForeignKey(UserDashboard)
system = models.ForeignKey(System)
system_group = models.ForeignKey(SystemGroup)
class UserGroupQuery(models.Model):
'''Queries that run in a specific group on the dashboard (ie. Within 'System 1's Key Indicators, we run queries for active users today, orders in the last hour, etc. '''
user = models.ForeignKey(User)
dashboard = ChainedForeignKey(UserDashboard, chained_field='user', chained_model_field='user', show_all=False, auto_choose=True)
user_dashboard_group = ChainedForeignKey(UserDashboardGroup, chained_field='dashboard', chained_model_field='dashboard')
query = models.ForeignKey(QueryData)
I am having problems with the very last part of this. I want to restrict the 'query' that appears in a admin page based on the selected user_dashboard_group. I'm not sure how I can do this, based on my current models though. query and user_dashboard_group both have a foreign key to System, but not to each other. To get this though, I'd have to get the user_dashboard_group's system and then use that to filter the QueryData. How can I do this?
Edit
I'm adding in a picture to (hopefully) describe a little better what I want to do.
In step 1, the user inputs a name for this group of queries. This group is associated with a system (#2) and a predefined group within the system (#3) (think of #3 as a 'customer' or a 'region', etc and #1 and #3 are NOT the same thing, despite the similar naming). They then select 'Save and Continue editing' on this inline form and the drop down at step 4 becomes populated with information from the above form. Once step #4 has a selection made, I want #5 to populate with data only from the associated system. Since #2 contains this information, I am hoping it is fairly easy to do this, but I can't figure out the chaining.
I also realized that I didn't mention I was using django-smart-selects
I have never worked with django-smart-selects, but following the docs, I would expect
query = models.ChainedForeignKey(QueryData,**kwargs)
instead of
query = models.ForeignKey(QueryData)
since you want the options in query depend on the other selections. Is that understanding correct? If so, it was only about defining the right **kwargs.
For **kwargs, I would propose something like this
Update
chained_field='query', chained_model_field='user_dashboard_group__system__query_set__query'
assuming that the fields name is 'system in both cases.
I am pretty sure that this describes the relationship correctly. I am just not sure, if django-smart-selects supports that syntax.
Same way you would do it across one relation, except across two.
field__relation1__relation2
I have been searching and looking through docs, but I want to ask and confirm for the best solution here.
Trying to define model choices.
'yes, no and not sure' choice From Radio Select
How would I define for Multiple Choices
Simple Example:
In my models.py, I have
class Property(models.Model):
name = models.CharField()
class Feature(models.Model):
YES_CHOICES = ( # example of 1, there can be only one selection
('YES', 'Yes'),
('NO', 'No'),
('NOT_SURE', 'Not Sure')
)
PARKING_CHOICES = ( # example of 2, there can be multiple selections
('GARAGE', 'Garage'),
('STREET', 'Street'),
('PRIVATE_LOT', 'Private Lot'),
('VALET', 'Valet'),
)
nearby_school = models.CharField(max_length=8, choices=YES_CHOICES)
parking_options = models. MultipleChoiceField(choices=PARKING_CHOICES)
class PropertyFeature(models.Model)
property = models.ForeignKey(Property)
feature = models.ForeignKey(Feature)
...
Are those best ways to do it?
Should I use NullBooleanField instead for yes, no , not sure question?
Is that a correct way for defining and storing for multiple choice answers? Sometimes, I see people using manytomany objects.
Just want to use the most efficient and the easiest method offered from Django.
18 months or so later, there is now a better way of dealing with choices in Django; Łukasz Langa's dj.choices. An example of its use, from the blog post introducing the project:
from dj.choices import Choices, Choice
class Gender(Choices):
male = Choice("male")
female = Choice("female")
not_specified = Choice("not specified")
class User(models.Model):
gender = models.IntegerField(choices=Gender(),
default=Gender.not_specified.id)
def greet(self):
gender = Gender.from_id(self.gender)
if gender == Gender.male:
return 'Hi, boy.'
elif gender == Gender.female:
return 'Hello, girl.'
else:
return 'Hey there, user!'
This still won't work for multiple selections, though.
Yes, NullBoolean is appropriate, but if there are more options that don't fit the profile of NullBoolean, I'm in favor of IntegerField for readability and consistency across options.
Null could intuitively mean n/a, but as you add more single choice questions, I think it's even more intuitive to use an IntegerField mapped to static variables.
Also for this type of scenario where the user will probably filter properties based on these features, it's useful not to have to special case Null in your dynamic query.
Example:
...filter(Q(nearby_school__isnull=True) | Q(nearby_school='NO')),
other_choice='SOME_CHOICE')
# vs
...filter(Q(nearby_school=Feature.NOT_SURE) | Q(nearby_school=Feature.NO)),
other_choice=Feature.SOME_CHOICE)
This ancient post still serves as a great reference:
http://www.b-list.org/weblog/2007/nov/02/handle-choices-right-way/
class Feature(models.Model):
YES = 0
NO = 1
NOT_SURE = 2
SOMETIMES = 3
YES_CHOICES = (
(YES, 'Yes'),
(NO, 'No'),
(NOT_SURE, 'Not Sure'),
(SOMETIMES, 'Sometimes'), # extensible.
)
As for a multiple choice field, I do think using a m2m field is the easiest/best way.
You could set up your forms.MultipleChoiceField to store data as a comma separated field & display appropriately, but the fact that you can query the m2m field easily is a huge benefit + it works right out of the box with ModelMultipleChoiceField.
I am converting a web project that currently uses the Propel ORM, to a django project.
My first task is to 'port' the model schema to django's.
I have read the django docs, but they do not appear to be in enough detail. Case in point, how may I 'port' a (contrived) table defined in the Propel YML schema as follows:
demo_ref_country:
code: { type: varchar(4), required: true, index: unique }
name: { type: varchar(64), required: true, index: unique }
geog_region_id: { type: integer, foreignTable: demo_ref_geographic_region, foreignReference: id, required: true, onUpdate: cascade, onDelete: restrict }
ccy_id: { type: integer, foreignTable: demo_ref_currency_def, foreignReference: id, required: true, onUpdate: cascade, onDelete: restrict }
flag_image_path: { type: varchar(64), required: true, default: ''}
created_at: ~
_indexes:
idx_f1: [geog_region_id, ccy_id, created_at]
_uniques:
idxu_f1_key: [code, geog_region_id, ccy_id]
Here is my (feeble) attempt so far:
class Country(models.Model):
code = models.CharField(max_length=4) # Erm, no index on this column .....
name = models.CharField(max_length=64) # Erm, no index on this column .....
geog_region_id = models.ForeignKey(GeogRegion) # Is this correct ? (how about ref integrity constraints ?
ccy_id = models.ForeignKey(Currency) # Is this correct?
flag_image_path = models.CharField(max_length=64) # How to set default on this col?
created_at = models.DateTimeField() # Will this default to now() ?
# Don't know how to specify indexes and unique indexes ....
[Edit]
To all those suggesting that I RTFM, I understand your frustration. Its just that the documentation is not very clear to me. It is probably a Pythonic way of documentation - but coming from a C++ background, I feel the documentation could be improved to make it more accesible for people coming from different languages.
Case in point: the documentation merely states the class name and an **options parameter in the ctor, but doesn't tell you what the possible options are.
For example class CharField(max_length=None,[**options])
There is a line further up in the documentation that gives a list of permissible options, which are applicable to all field types.
However, the options are provided in the form:
Field.optionname
The (apparently implicit) link between a class property and a constructor argument was not clear to me. It appears that if a class has a property foo, then it means that you can pass an argument named foo to its constructor. Does that observation hold true for all Python classes?
The indexes are automatically generated for your references to other models (i.e. your foreign keys). In other words: your geog_region_id is correct (but it would be better style to call it geog_region).
You can set default values using the default field option.
import datetime
class Country(models.Model):
code = models.CharField(max_length=4, unique=True)
name = models.CharField(max_length=64)
geog_region = models.ForeignKey(GeogRegion)
ccy = models.ForeignKey(Currency, unique=True)
flag_image_path = models.CharField(max_length=64, default='')
created_at = models.DateTimeField(default=datetime.now())
(I'm no expert on propel's orm)
Django always tries to imitate the "cascade on delete" behaviour, so no need to specify that somewhere. By default all fields are required, unless specified differently.
For the datetime field see some more options here. All general field options here.
code = models.CharField(max_length=4) # Erm, no index on this column .....
name = models.CharField(max_length=64) # Erm, no index on this column .....
You can pass the unique = True keyword argument and value for both of the above.
geog_region_id = models.ForeignKey(GeogRegion) # Is this correct ? (how about ref integrity constraints ?
ccy_id = models.ForeignKey(Currency) # Is this correct?
The above lines are correct if GeogRegion and Currency are defined before this model. Otherwise put quotes around the model names. For e.g. models.ForeignKey("GeogRegion"). See documentation.
flag_image_path = models.CharField(max_length=64) # How to set default on this col?
Easy. Use the default = "/foo/bar" keyword argument and value.
created_at = models.DateTimeField() # Will this default to now() ?
Not automatically. You can do default = datetime.now (remember to first from datetime import datetime). Alternately you can specify auto_now_add = True.
# Don't know how to specify indexes and unique indexes ....
Take a look at unique_together.
You'll see that the document I have linked to is the same pointed out by others. I strongly urge you to read the docs and work through the tutorial.
I'm sorry, you haven't read the docs. A simple search for index, unique or default on the field reference page reveals exactly how to set those options.
Edit after comment I don't understand what you mean about multiple lines. Python doesn't care how many lines you use within brackets - so this:
name = models.CharField(unique=True, db_index=True)
is exactly the same as this:
name = models.CharField(
unique=True,
db_index=True
)
Django doesn't support multi-column primary keys, but if you just want a multi-column unique constraint, see unique_together.
Class demo_ref_country(models.Model)
code= models.CharField(max_length=4, db_index=True, null=False)
name= models.CharField(max_length=64, db_index=True, null=False)
geog_region = models.ForeignKey(geographic_region, null=False)
ccy = models.ForeignKey(Currency_def, null=False)
flag = models.ImageField(upload_to='path to directory', null=False, default="home")
created_at = models.DateTimeField(auto_now_add=True, db_index=True)
class Meta:
unique_together = (code, geog_region, ccy)
You can set default values,, db_index paramaeter creates indexes for related fields. You can use unique=True for seperate fields, but tahat unique together will check uniqueness in columns together.
UPDATE: First of all, i advice you to read documentatin carefully, since django gives you a lot of opportunuties, some of them have some restrictions... Such as, unique_together option is used just for django admin. It means if you create a new record or edit it via admin interface, it will be used. If you will alsa insert data with other ways (like a DataModel.objects.create statement) its better you use uniaue=True in field definition like:
code= models.CharField(max_length=4, db_index=True, null=False, unique=True)
ForeignKey fields are unique as default, so you do not need to define uniqueness for them.
Django supports method override, so you can override Model save and delete methods as you like.
check it here. Django also allows you to write raw sql queries you can check it here
As i explained, unique together is a django admin feature. So dont forget to add unique=True to required fields.
Unique together also allows you to define diffrent unique pairs, such as;
unique_together = (('id','code'),('code','ccy','geog_region'))
That means, id and code must be unique together and code, ccy and geog_region must be unique together
UPDATE 2: Prior to your question update...
It is better yo start from tutorials. It defines basics with good examples.
As for doc style, let me give you an example, but if you start from tutors, it will be easier for you...
There are from model structure... Doc here
BooleanField
class BooleanField(**options)
that defines, the basic structure of a database field, () is used, and it has some parameters taken as options. that is the part:
models.BooleansField()
Since this is a field struvture, available options are defines as:
unique
Field.unique
So,
models.BooleansField(unique=True)
That is the general usage. Since uniqu is a basic option available to all field types, it classified as field.unique. There are some options available to a single field type, like symmetrical which is a ManyToMany field option, is classified as ManyToMany.Symmetrical
For the queryset
class QuerySet([model=None])
That is used as you use a function, but you use it to filter a model, with other words, write a filter query to execute... It has some methods, like filter...
filter(**kwargs)
Since this takes some kwargs, and as i told before, this is used to filter your query results, so kwargs must be your model fields (database table fields) Like:
MyModel.objects.filter(id=15)
what object is defines in the doc, but it is a manager that helps you get related objects.
Doc contains good examples, but you have to start from tutors, that is what i can advice you...