Django admin Add form - Limit number of displayed Model by foreign key when date is within range

Question

Consider I have the below simple model:

class Dimdate(models.Model):
  id = models.AutoField(db_column='Id', primary_key=True)  # Field name made lowercase.
  date = models.DateField(db_column='date')  # Field name made lowercase.

This table is used by many others models (so Dimdate.id is the FK) as below:

class MyModel(models.Model):
  id = models.AutoField(db_column='Id', primary_key=True)  # Field name made lowercase.
  dateid = models.ForeignKey(Dimdate, models.DO_NOTHING, db_column='DateId', blank=True, null=True)  # Field name made lowercase.
  # ...

My problem is that DimDate table contains too many records. When using Django admin UI to add a new MyModel instance, the dropdown menu is showing all of my DimDate which makes it not user friendly.

I did a quick google search but found nothing to restrict the number of DimDate elements retrieved and displayed in the dropdown menu (when adding a MyModel instance). Can I filter my dimdate to include only the dates from 1 month in the past to 1 month in the future?

Eg: If we are the 27th of Jan 2020. Dates range is: [27/12/2019, 27/02/2020]

I am currently using the admin "classic" approach of django (no custom form):

@admin.register(models.MyModel)
class MyModelAdmin(admin.ModelAdmin):

I suspect I will need to override the MyModel form. But even by doing it. How can I limit the number of retrieved DimDate inside my form?

Is there an easier way of doing (as I am new with Django...)?

In case it is needed, I am using Django 2.2.6

Answer 1

use raw_id_fields in your admin config to prevent loading all objects

@admin.register(models.MyModel)
class MyModelAdmin(admin.ModelAdmin):
    raw_id_fields = ('dateid',)`

it shows up like bellow and you can select object when clicking on it on new window

and if you want just filter dropdown items you can add limit_choices_to to you foreignkey field like bellow:

def limit_dim_date_choices():
    return {'date__range': (date(2019,12,27), date(2020,2,27))}

class MyModel(models.Model):
  id = models.AutoField(db_column='Id', primary_key=True)  # Field name made lowercase.
  dateid = models.ForeignKey(Dimdate, limit_choices_to=limit_dim_date_choices, models.DO_NOTHING, db_column='DateId', blank=True, null=True)  # Field name made lowercase.
  # ...