I have a django ap which has a rather complicated model setup. I created a layered composition to create a hierarchical model. All relations are with each other, so I could use inheritance, but I decided not to make it profitable to have a composition of objects for my models, which means that I can do things like
product.outerframe.top.cost
which do the complex calculations that I have to transform are much better organized.
However, this model allows you to use the django admin. I basically have a through table, i.e. An external table is just a bunch of foreign keys for other tables (with a unique constraint for each). I ended up using the add_view () and change_view () methods of ModelAdmin, which is pretty complicated.
Is there an easier way to deal with many or many tables when using the django admin?
The tables are arranged as follows:
Product> outer frame, inner frame, glass, other
outer frame> top, bottom, side, etc.
innerframe> top, bottom, side, etc.
glass> glass_type etc.
other> accessories, etc.
Here are my models:
class Product(mixins.ProductVariables):
name = models.CharField(max_length=255)
sku = models.CharField(max_length=100, unique=True, db_index=True)
image = thumbnail.ImageField(upload_to='product_images', blank=True)
description = models.TextField(blank=True)
group = models.ForeignKey('ProductGroup', related_name='products', null=True)
hidden = models.BooleanField(default=False)
product_specific_mark_up = models.DecimalField(default=1.0, max_digits=5,decimal_places=2)
def total_material_cost(self, width, height, options):
return sum([
self.outerframe.cost(width, height, options),
self.innerframe.cost(width, height, options),
self.glass.cost(width, height, options),
self.other.cost(width, height, options),
])
def total_labour_time(self, width, height, options):
return sum([
self.outerframe.labour_time(width, height, options),
self.innerframe.labour_time(width, height, options),
self.glass.labour_time(width, height, options),
self.other.labour_time(width, height, options),
])
def total_co2_output(self, width, height, options):
return sum([
self.outerframe.co2_output(width, height, options),
self.innerframe.co2_output(width, height, options),
self.glass.co2_output(width, height, options),
self.other.co2_output(width, height, options),
])
@property
def max_overall_width(self):
return 1000
@property
def max_overall_height(self):
return 1000
def __unicode__(self):
return self.name
class OuterFrame(models.Model, mixins.GetFieldsMixin, mixins.GetRelatedClassesMixin):
top = models.OneToOneField(mixins.TopFrame)
bottom = models.OneToOneField(mixins.BottomFrame)
side = models.OneToOneField(mixins.SideFrame)
accessories = models.OneToOneField(mixins.Accessories)
flashing = models.OneToOneField(mixins.Flashing)
silicone = models.OneToOneField(mixins.Silicone)
product = models.OneToOneField(Product)
def cost(self, width, height, options):
return sum([
self.top.cost * (width / 1000),
self.bottom.cost * (width / 1000),
self.side.cost * (width*2 / 1000),
])
def labour_time(self, width, height, options):
return datetime.timedelta(minutes=100)
def CO2_output(self, width, height, options):
return 100
@classmethod
def get_fields(cls):
options = cls._meta
fields = {}
for field in options.fields:
if field.name == 'product':
continue
if isinstance(field, models.OneToOneField):
related_cls = field.rel.to
related_fields = fields_for_model(related_cls, fields=related_cls.get_fields())
fields.update( { related_cls.__name__ + '_' + name:field for name, field in related_fields.iteritems() })
return fields
class InnerFrame(models.Model, mixins.GetFieldsMixin, mixins.GetRelatedClassesMixin):
top = models.OneToOneField(mixins.TopFrame)
bottom = models.OneToOneField(mixins.BottomFrame)
side = models.OneToOneField(mixins.SideFrame)
accessories = models.OneToOneField(mixins.Accessories)
product = models.OneToOneField(Product)
def cost(self, width, height, options):
print self.top.cost
return sum([
self.top.cost * (width / 1000),
self.bottom.cost * (width / 1000),
self.side.cost * (width*2 / 1000),
])
def labour_time(self, width, height, options):
return datetime.timedelta(minutes=100)
def CO2_output(self, width, height, options):
return 100
class Glass(models.Model, mixins.GetRelatedClassesMixin):
glass_type_a = models.OneToOneField(mixins.GlassTypeA)
glass_type_b = models.OneToOneField(mixins.GlassTypeB)
enhanced = models.OneToOneField(mixins.Enhanced)
laminate = models.OneToOneField(mixins.Laminate)
low_iron = models.OneToOneField(mixins.LowIron)
privacy = models.OneToOneField(mixins.Privacy)
anti_slip = models.OneToOneField(mixins.AntiSlip)
heat_film_mirror = models.OneToOneField(mixins.HeatMirrorField)
posished_edges = models.OneToOneField(mixins.PolishedEdges)
product = models.OneToOneField(Product)
def cost(self, width, height, options):
return sum([
])
def labour_time(self, width, height, options):
return datetime.timedelta(minutes=100)
def CO2_output(self, width, height, options):
return 100
class Other(models.Model, mixins.GetRelatedClassesMixin):
num_packages = models.OneToOneField(mixins.NumberPackages)
product = models.OneToOneField(Product)
def cost(self, width, height, options):
return 100
def labour_time(self, width, height, options):
return datetime.timedelta(minutes=100)
def CO2_output(self, width, height, options):
return 100
Impurities:
class TimeCostMixin(models.Model, GetFieldsMixin):
cost = models.DecimalField(default=0.0, max_digits=10, decimal_places=2)
time = models.TimeField(default=datetime.timedelta(0))
class Meta:
abstract = True
class FrameComponentMixin(TimeCostMixin):
external_width = models.IntegerField(default=0)
material_weight = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
u_value = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
class Meta:
abstract = True
class TopFrame(FrameComponentMixin):
pass
class BottomFrame(FrameComponentMixin):
pass
class SideFrame(FrameComponentMixin):
pass
class Accessories(TimeCostMixin):
material_weight = models.DecimalField(default=0.0,max_digits=10,decimal_places=2)
class Flashing(TimeCostMixin):
pass
class Silicone(TimeCostMixin):
labour_time = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
class GlassTypeA(TimeCostMixin):
material_weight = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
u_value = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
class GlassTypeB(TimeCostMixin):
material_weight = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
u_value = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
class Enhanced(TimeCostMixin):
material_weight = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
class Laminate(TimeCostMixin):
material_weight = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
class LowIron(TimeCostMixin):
pass
class Privacy(TimeCostMixin):
pass
class AntiSlip(TimeCostMixin):
pass
class HeatMirrorField(TimeCostMixin):
u_value = models.DecimalField(default=0.0, max_digits=10,decimal_places=2)
class PolishedEdges(models.Model):
cost = models.DecimalField(default=0.0, max_digits=10, decimal_places=2)
class NumberPackages(models.Model):
number_of_packages = models.IntegerField(default=0)
and hair extension by the administrator!
class ProductAdmin(AdminImageMixin, admin.ModelAdmin):
inlines = [ProductDownloadInline, ProductConfigurationInline]
add_form_template = 'admin/products/add_form.html'
change_form_template = 'admin/products/add_form.html'
@csrf_protect_m
@transaction.atomic
def add_view(self, request, form_url='', extra_context=None):
extra_context = extra_context or {}
"The 'add' admin view for this model."
model = self.model
opts = model._meta
if not self.has_add_permission(request):
raise PermissionDenied
ModelForm = self.get_form(request)
formsets = []
inline_instances = self.get_inline_instances(request, None)
if request.method == 'POST':
form = ModelForm(request.POST, request.FILES)
if form.is_valid():
new_object = self.save_form(request, form, change=False)
form_validated = True
else:
form_validated = False
new_object = self.model()
prefixes = {}
for FormSet, inline in zip(self.get_formsets(request), inline_instances):
prefix = FormSet.get_default_prefix()
prefixes[prefix] = prefixes.get(prefix, 0) + 1
if prefixes[prefix] != 1 or not prefix:
prefix = "%s-%s" % (prefix, prefixes[prefix])
formset = FormSet(data=request.POST, files=request.FILES,
instance=new_object,
save_as_new="_saveasnew" in request.POST,
prefix=prefix, queryset=inline.get_queryset(request))
formsets.append(formset)
outer_frame_forms = [
modelform_factory(cls)(request.POST, prefix='OuterFrame_'+cls.__name__)
for cls in models.OuterFrame.get_related_classes(exclude=['product'])
]
inner_frame_forms = [
modelform_factory(cls)(request.POST, prefix='InnerFrame'+cls.__name__)
for cls in models.InnerFrame.get_related_classes(exclude=['product'])
]
glass_forms = [
modelform_factory(cls)(request.POST, prefix='InnerFrame'+cls.__name__)
for cls in models.Glass.get_related_classes(exclude=['product'])
]
other_forms = [
modelform_factory(cls)(request.POST, prefix='InnerFrame'+cls.__name__)
for cls in models.Other.get_related_classes(exclude=['product'])
]
if all_valid(formsets
+outer_frame_forms
+inner_frame_forms
+glass_forms
+other_forms
) and form_validated:
self.save_model(request, new_object, form, False)
self.save_related(request, form, formsets, False)
self.log_addition(request, new_object)
inner_frame = models.InnerFrame()
inner_frame.product = new_object
mapping = {f.rel.to:f.name for f in models.InnerFrame._meta.fields if f.name not in ['id','product']}
for f in inner_frame_forms:
obj = f.save()
setattr(inner_frame, mapping[obj.__class__], obj)
inner_frame.save()
outer_frame = models.OuterFrame()
outer_frame.product = new_object
mapping = {f.rel.to:f.name for f in models.OuterFrame._meta.fields if f.name not in ['id','product']}
for f in outer_frame_forms:
obj = f.save()
setattr(outer_frame, mapping[obj.__class__], obj)
outer_frame.save()
glass = models.Glass()
glass.product = new_object
mapping = {f.rel.to:f.name for f in models.Glass._meta.fields if f.name not in ['id','product']}
for f in glass_forms:
obj = f.save()
setattr(glass, mapping[obj.__class__], obj)
glass.save()
other = models.Other()
other.product = new_object
mapping = {f.rel.to:f.name for f in models.Other._meta.fields if f.name not in ['id','product']}
for f in other_forms:
obj = f.save()
setattr(other, mapping[obj.__class__], obj)
other.save()
return self.response_add(request, new_object)
else:
forms = SortedDict({})
forms['Outer Frame Variables'] = {
cls.__name__: modelform_factory(cls)(prefix='OuterFrame_'+cls.__name__)
for cls in models.OuterFrame.get_related_classes(exclude=['product'])
}
forms['Inner Frame Variables'] = {
cls.__name__: modelform_factory(cls)(prefix='InnerFrame'+cls.__name__)
for cls in models.InnerFrame.get_related_classes(exclude=['product'])
}
forms['Glass Variables'] = {
cls.__name__: modelform_factory(cls)(prefix='InnerFrame'+cls.__name__)
for cls in models.Glass.get_related_classes(exclude=['product'])
}
forms['Other Variables'] = {
cls.__name__: modelform_factory(cls)(prefix='InnerFrame'+cls.__name__)
for cls in models.Other.get_related_classes(exclude=['product'])
}
extra_context['forms'] = forms
initial = dict(request.GET.items())
for k in initial:
try:
f = opts.get_field(k)
except models.FieldDoesNotExist:
continue
if isinstance(f, models.ManyToManyField):
initial[k] = initial[k].split(",")
form = ModelForm(initial=initial)
prefixes = {}
for FormSet, inline in zip(self.get_formsets(request), inline_instances):
prefix = FormSet.get_default_prefix()
prefixes[prefix] = prefixes.get(prefix, 0) + 1
if prefixes[prefix] != 1 or not prefix:
prefix = "%s-%s" % (prefix, prefixes[prefix])
formset = FormSet(instance=self.model(), prefix=prefix,
queryset=inline.get_queryset(request))
formsets.append(formset)
adminForm = helpers.AdminForm(form, list(self.get_fieldsets(request)),
self.get_prepopulated_fields(request),
self.get_readonly_fields(request),
model_admin=self)
media = self.media + adminForm.media
inline_admin_formsets = []
for inline, formset in zip(inline_instances, formsets):
fieldsets = list(inline.get_fieldsets(request))
readonly = list(inline.get_readonly_fields(request))
prepopulated = dict(inline.get_prepopulated_fields(request))
inline_admin_formset = helpers.InlineAdminFormSet(inline, formset,
fieldsets, prepopulated, readonly, model_admin=self)
inline_admin_formsets.append(inline_admin_formset)
media = media + inline_admin_formset.media
context = {
'title': _('Add %s') % force_text(opts.verbose_name),
'adminform': adminForm,
'is_popup': IS_POPUP_VAR in request.REQUEST,
'media': media,
'inline_admin_formsets': inline_admin_formsets,
'errors': helpers.AdminErrorList(form, formsets),
'app_label': opts.app_label,
'preserved_filters': self.get_preserved_filters(request),
}
context.update(extra_context or {})
return self.render_change_form(request, context, form_url=form_url, add=True)