So you have a least two ways of checking that. First is to create try/catch block to get attribute, second is to use hasattr. class A(models.Model): def get_B(self): try: return self.b except: return None class B(models.Model): ref_a = models.OneToOneField(related_name=”ref_b”, null=True) Please try to avoid bare except: clauses. It can hide some problems. The second way … Read more
I assume that you are going to have more than a few of these multiple-choice attributes, and would like to keep things tidy. I would recommend the store it in the database approach only if you want to modify the choices at runtime, otherwise it would quickly become a performance hit; If a model has … Read more
If you are only concerned with how your FloatField appears in forms, you can use the template filter floatformat. From the Django Docs: If used with a numeric integer argument, floatformat rounds a number to that many decimal places. For example, if value = 34.23234, then in your template: {{ value|floatformat:2 }} # outputs 34.23
The solution is to NOT include any custom message keys in the models, like… :message => I18n.t(‘activerecord.errors.models.my_model.attributes.whatever.please_select_whatever’) The model will then apply the default message keys, for example “:inclusion” in the case of “validates_inclusion_of” …and in config/locales/en.yml you need to have: en: activerecord: errors: models: my_model: attributes: whatever: inclusion: “Please select whatever.” # see default … Read more
This is a self-referential model, you can try something like this: class Event < ActiveRecord::Base belongs_to :parent, :class_name => “Event”, :foreign_key => “parent_event_id” has_many :child_events, :class_name => “Event”, :foreign_key => “child_event_id” end That way, you can call @event.parent to get an ActiveRecord Event object and @event.child_events to get an ActiveRecord collection of Event objects
Rails supports Single Table Inheritance. From the AR docs: Active Record allows inheritance by storing the name of the class in a column that by default is named “type” (can be changed by overwriting Base.inheritance_column). This means that an inheritance looking like this: class Company < ActiveRecord::Base; end class Firm < Company; end class Client … Read more
The app_label is available as an attribute on the _meta attribute of any model. from django.contrib.auth.models import User print User._meta.app_label # The object name is also available print User._meta.object_name
Use the static query method: $query = User::query(); Additionally, you can use the when method to chain these conditionals directly onto the query builder itself: $results = SomeModel::query()->when(condition(), function ($query) { $query->where(…); })->get(); This is functionally equivalent to the imperative if clause.
If you need to do something to the data before saving, just create a function like: def clean_nameofdata(self): data = self.cleaned_data[‘nameofdata’] # do some stuff return data All you need is to create a function with the name **clean_***nameofdata* where nameofdata is the name of the field, so if you want to modify password field, … Read more
class Model include ActiveModel::Validations include ActiveModel::Conversion extend ActiveModel::Naming attr_accessor :whatever validates :whatever, :presence => true def initialize(attributes = {}) attributes.each do |name, value| send(“#{name}=”, value) end end def persisted? false end end attr_accessor will create your attributes and you will create the object with initialize() and set attributes. The method persisted will tell there is … Read more