many-to-many

问题 The following is for a creative writing app. All aspects (characters, scenes, projects etc.) are recorded in the same model to allow for a simple sidebar directory. Each have extension models to add specific fields, so when an element is selected in the sidebar, the extension model is loaded as a form on the right. Extension model additional fields and universe model excluded for clarity. The problem is, I'm really stuck with restricting choices on a specific ManytoMany field. MODELS.PY class

问题 i want to to update field whenever an instance been created i tried signals but it seems complicate to ManyToManyField class MobileCustomer(models.Model): customer = models.CharField(max_length=30) phone = models.CharField(max_length=13) mobile = models.ManyToManyField(MobileStorage,through='SelectMobile') class SelectMobile(models.Model): mobile = models.ForeignKey(MobileStorage,on_delete=models.CASCADE) item = models.ForeignKey(MobileCustomer,on_delete=models.CASCADE) quantity = models

问题 i want to to update field whenever an instance been created i tried signals but it seems complicate to ManyToManyField class MobileCustomer(models.Model): customer = models.CharField(max_length=30) phone = models.CharField(max_length=13) mobile = models.ManyToManyField(MobileStorage,through='SelectMobile') class SelectMobile(models.Model): mobile = models.ForeignKey(MobileStorage,on_delete=models.CASCADE) item = models.ForeignKey(MobileCustomer,on_delete=models.CASCADE) quantity = models

问题 I'm using Django 2.2 and FactoryBoy to attempt to create some factories to produce the following models ... class CoopType(models.Model): name = models.CharField(max_length=200, null=False) objects = CoopTypeManager() class Meta: # Creates a new unique constraint with the `name` field constraints = [models.UniqueConstraint(fields=['name'], name='coop_type_unq')] class Coop(models.Model): objects = CoopManager() name = models.CharField(max_length=250, null=False) types = models.ManyToManyField

问题 I want to be able to update a many-to-many field on a model, when the name of the field is stored in a variable. This is relatively easy for a normal field (with kwargs in the constructor), or even a foreign key, but not so for a many-to-many field. Here's the situation: class Book(models.Model): title = models.CharField(max_length=30) authors = models.ManyToManyField(Author) field_name = 'title' new = Book(**{field_name:'My Book'}) # This sets title to mybook new.save() my_authors = Author

问题 Here's what I want to achieve, we have Staff and every staff can have one Position for a department, as well as one Designation for a department and multiple Additional Charges for multiple departments, one department per Additional Charge . And I want to store all the responsibilities in the staff_responsibilities table I have a staff table with the following columns id name email Then I have staff_responsibilities table with the following columns: staff_id designation_id department_id

问题 How to get all table names in a Django app? I use the following code but it doesn't get the tables created by ManyToManyField from django.db.models import get_app, get_models app = get_app(app_name) for model in get_models(app): print model._meta.db_table 回答1: from django.db import connection tables = connection.introspection.table_names() seen_models = connection.introspection.installed_models(tables) As seen in the syncdb command for manage.py. In a comment below, years after the answer

问题 How to get all table names in a Django app? I use the following code but it doesn't get the tables created by ManyToManyField from django.db.models import get_app, get_models app = get_app(app_name) for model in get_models(app): print model._meta.db_table 回答1: from django.db import connection tables = connection.introspection.table_names() seen_models = connection.introspection.installed_models(tables) As seen in the syncdb command for manage.py. In a comment below, years after the answer

问题 py which looks like below class Scenes(models.Model): name = models.CharField(max_length=30) def __str__(self): return self.name class Tech(models.Model): tech = models.CharField(max_length=30) scenario = models.ManyToManyField('Scenes') def __str__(self): return self.tech class UserLog(models.Model): tech_id = models.ForeignKey(Tech, on_delete=models.CASCADE) ....#other fields It generates one extra table called pages_tech_scenario (pages is my app name) My populated tables in database

问题 We have an entity Role which could be either users or groups. In the groups we have set permissions. Therefore a user belongs to a group. Additionally groups can belong to other groups, i.e. one could make a hierarchy of permissions. The idea is to store the relations from e.g. user -> group into a separate db table role_ref . @Table(name = "role__parent") @IdClass(RoleAssociationKey.class) @Data public class RoleAssociation implements Serializable { @Id @JoinColumn(name = "has_parent_role_id