django-velcro example for https://www.reddit.com/r/django/comments/3ddvo7/lets_talk_genericforeignkeys/

01-actual-code-written.py

###############
# settings.py #
###############

RELATIONSHIPS = [
    ('alerts', 'insurers'),
    ('alerts', 'producers'),
    ('alerts', 'vendors'),
]


#############
# models.py #
#############

from django.conf import settings
from django.db import models

def relations_base(object_type):
    if 'django_velcro' in settings.INSTALLED_APPS:
        from django_velcro.utils import relations_abstract_base
        RelationsBase = relations_abstract_base(object_type)
    else:
        RelationsBase = models.Model
    return RelationsBase


class Alert(relations_base('alerts')):
    ...


class Insurer(relations_base('insurers')):
    ...


class Producer(relations_base('producers')):
    ...


class Vendor(relations_base('vendors')):
    ...


############
# admin.py #
############

from django.conf import settings
from django.contrib import admin

from .models import Alert, Insurer, Producer, Vendor

def admin_base(object_type):
    if 'django_velcro' in settings.INSTALLED_APPS:
        from django_velcro.utils import generic_admin_base
        GenericAdminBase = generic_admin_base(object_type)
    else:
        GenericAdminBase = admin.ModelAdmin
    return GenericAdminBase


@admin.register(Alert)
class AlertAdmin(admin_base('alerts')):
    pass

@admin.register(Insurer)
class InsurerAdmin(admin_base('insurers')):
    pass

@admin.register(Producer)
class ProducerAdmin(admin_base('producers')):
    pass

@admin.register(Vendor)
class VendorAdmin(admin_base('vendors')):
    pass

02-what-code-is-equivalent-to.py

#############
# models.py #
#############

from django.conf import settings
from django.db import models

from django_velcro import (AlertsInsurersRelationship,
    AlertsProducersRelationship, AlertsVendorsRelationship)

class Alert(models.Model):
    related_insurers = GenericRelation(AlertsInsurersRelationship,
        content_type_field='insurers_content_type',
        object_id_field='insurers_object_id',
        related_query_name='alerts',
    )
    related_producers = GenericRelation(AlertsProducersRelationship,
        content_type_field='producers_content_type',
        object_id_field='producers_object_id',
        related_query_name='alerts',
    )
    related_vendors = GenericRelation(AlertsVendorsRelationship,
        content_type_field='vendors_content_type',
        object_id_field='vendors_object_id',
        related_query_name='alerts',
    )


class Insurer(models.Model):
    related_alerts = GenericRelation(AlertsInsurersRelationship,
        content_type_field='alerts_content_type',
        object_id_field='alerts_object_id',
        related_query_name='insurers',
    )


class Producer(models.Model):
    related_alerts = GenericRelation(AlertsProducersRelationship,
        content_type_field='alerts_content_type',
        object_id_field='alerts_object_id',
        related_query_name='producers',
    )


class Vendor(models.Model):
    related_alerts = GenericRelation(AlertsVendorsRelationship,
        content_type_field='alerts_content_type',
        object_id_field='alerts_object_id',
        related_query_name='vendors',
    )


############
# admin.py #
############

from django.conf import settings
from django.contrib import admin

from django_velcro.admin import (AlertsToInsurersAdminBase,
    AlertsToProducersAdminBase, AlertsToVendorsAdminBase,
    InsurersToAlertsAdminBase, ProducersToAlertsAdminBase,
    VendorsToAlertsAdminBase
from genericadmin.admin import GenericAdminModelAdmin

from .models import Alert, Insurer, Producer, Vendor


@admin.register(Alert)
class AlertAdmin(GenericAdminModelAdmin):
    inlines = [
        AlertsToInsurersAdminBase,
        AlertsToProducersAdminBase,
        AlertsToVendorsAdminBase,
    ]

@admin.register(Insurer)
class InsurerAdmin(GenericAdminModelAdmin):
    inlines = [InsurersToAlertsAdminBase]

@admin.register(Producer)
class ProducerAdmin(GenericAdminModelAdmin):
    inlines = [ProducersToAlertsAdminBase]

@admin.register(Vendor)
class VendorAdmin(GenericAdminModelAdmin):
    inlines = [VendorsToAlertsAdminBase]