On 21/12/2016 9:10 PM, C. Kirby wrote:
Mike, I've done a lot of work with Model meta, and I'm pretty sure I
can give you at least the bones of a solution, but I can't really get
my head around the problem. Could you post a set of related models and
what you would expect the result to look like?
I have a main model (substance) with a bunch of child models
(properties, toxicity, health, spill etc) containing TextFields with
advice for that substance. There are obviously lots of substances and
they carry varying advice in their child models. Two of them are MMA
and Styrene.
With a new substance (eg Base Resin CK90) which is a mixture of those
two substances, the chemical manufacturer needs to assemble advice in
those same TextFields in the CK90 mixture as the ones in the child
models carrying the varying advice. In some cases that advice (eg spill
advice) can come out of an expert's head and just be typed in. In some
cases the expert may prefer to see the spill advice from all the
ingredient substances first. Like so ... [1]
... editing out the ingredient names - in this case MMA and Styrene -
and combining the advice for the mixture, getting rid of redundant or
repetitive advice.
The concat_fields method which sources the advice only works for a
mixture (ie substance has ingredients). It only works on a blank field
or (when signalled) replaces advice from one or more ingredients. The
user deletes one (or more) of the ingredient names and inserts an
ellipsis in the CK90 field. The advice from that/those ingredient(s)
will be appended. If another ingredient is added to the mixture and an
ellipsis is inserted in the CK90 mixture TextField, the new ingredient
advice is appended.
The models are pretty standard ... there are more than the 1:1 (Spill)
and 1:n (Exposure) shown here.
Substance (main model)
ingredients = models.ManyToManyField('self', symmetrical=False,
blank=True,
through='Substance_Ingredients',)
Substance_Ingredients (m2m 'through' table)
substance = models.ForeignKey('Substance')
ingredient = models.ForeignKey('Substance')
proportion = models.DecimalField()
Spill (1:1 model)
substance = models.OneToOneField('Substance')
small = models.TextField(verbose_name="Small spill",
help_text="Response recommended for spills around 25 litres.")
Exposure (1:n model)
substance = models.ForeignKey('Substance', related_name='route')
symptoms = models.TextField(help_text="Potential adverse health
effects and symptoms from "
"the first at lowest exposure through to consequences of severe
exposure.")
Thanks CK
Mike
[1] For those not seeing the embedded image, it is a TextField
containing the following words:
Methyl methacrylate monomer: Soak up with inert absorbent material (e.g.
silica gel, acid binder, universal binder, sawdust). Keep in suitable,
closed containers for disposal.
Styrene: Soak up with inert absorbent material (e.g. sawdust). Keep in
closed containers for disposal.
On Wednesday, December 21, 2016 at 4:55:49 AM UTC+2, Mike Dewhirst wrote:
Bumping this question again, I have done all the individual
concatenations with the following model method ...
def concat_fields(self, ingredients):
""" ingredients is a queryset of substance:substance m2m records
with the second FK to substance in a field called "ingredient"
Objective is concatenate text from all text fields into the
mixture
"""
if ingredients:
objects = list()
ellip = "..."
for m2m in ingredients:
obj = m2m.ingredient.get_health()
if obj:
objects.append(obj)
if objects:
# first of seven text fields in this model
comment = self.ototoxic_comment or ""
comment = comment.strip()
if comment:
comment = "{0}\n".format(comment.strip())
if not comment or ellip in comment:
for obj in objects:
if not obj.substance.name
<http://obj.substance.name> in comment:
if obj.ototoxic_comment:
comment = "{0}{1}:
{2}\n".format(comment,
obj.substance.name <http://obj.substance.name>, obj.ototoxic_comment)
if comment:
self.ototoxic_comment =
comment.replace(ellip, "")
# next of seven text fields in this model and so on
...
There are 90 occurrences of this pattern in 18 concat_fields()
methods
in 18 models which are all much the same.
This offends me but I don't know how to start on the necessary "meta"
programming to make it somewhat more elegant.
Here is the on-screen help text for the user ...
"For mixtures, expandable blank fields "\
"below will be populated with ingredient data from the same
fields. "\
"Edit as required. To retrieve that data again add an ellipsis
(...) "\
"somewhere in the field and click [Save]"
Any advice would be appreciated. And appreciation might involve
red wine.
Thanks
Mike
On 7/12/2016 9:38 AM, Mike Dewhirst wrote:
> Consider a chemical mixture with a bunch of ingredients. Both
mixture
> and ingredients are instances of the same class so they have the
same
> fields. They also have many related models, including 1:1, 1:n
and n:m.
>
> Each related model will have none or many TextField's.
>
> The objective is to programmatically fill empty mixture text fields
> with concatenated content from the ingredients. The concatenated
> content would be separated by ingredient name titles for the
user to
> deal with the content more easily.
>
> I don't necessarily need all mixture text fields filled this way
but
> it certainly makes sense for some. With a couple of related
models I'd
> concatenate all text fields, with most though I'd like to pick and
> choose by field name and I'd ignore some models completely.
>
> The following model method is working properly as described but
it is
> mostly boiler-plate. It also only covers the first few of a large
> number of related models with text fields. If I keep using this
> technique it will add hundreds of LOC. Yuk.
>
> The question is how can I refactor this and make it generic?
Perhaps
> using the _meta API?
>
> Any guidance appreciated
>
>
> (In the abstract ancestor class of the Solid, Liquid and Gas
classes)
>
> def concat_fields(self, ingredients):
> """ ingredients is a queryset of substance-to-substance m2m
records.
> A substance has one physical state object being gas, liquid
or solid
> each of which inherits from core_fields and the fields
*here* we wish
> to concatenate text from (at the moment) all come from
core_fields.
> """
> assert ingredients
> # populate the list of ingredient physical state objects
> state_objs = list()
> for m2m in ingredients:
> state_objs.append(m2m.ingredient.get_physical_state_object())
>
> # get the text concatenated
> if not self.stability_comment:
> comment = ""
> for obj in state_objs:
> if obj.stability_comment:
> name = obj.substance.name
<http://obj.substance.name>
> text = obj.stability_comment
> comment = "{0}\n{1}: {2}".format(comment, name,
text)
> comment = comment.strip()
> if comment:
> self.stability_comment = comment
>
> if not self.reactivity:
> comment = ""
> for obj in state_objs:
> if obj.reactivity:
> name = obj.substance.name
<http://obj.substance.name>
> text = obj.reactivity
> comment = "{0}\n{1}: {2}".format(comment, name,
text)
> comment = comment.strip()
> if comment:
> self.reactivity = comment
>
> if not self.reaction_hazards:
> comment = ""
> for obj in state_objs:
> if obj.reaction_hazards:
> name = obj.substance.name
<http://obj.substance.name>
> text = obj.reaction_hazards
> comment = "{0}\n{1}: {2}".format(comment, name,
text)
> comment = comment.strip()
> if comment:
> self.reaction_hazards = comment
>
> if not self.avoid:
> comment = ""
> for obj in state_objs:
> if obj.avoid:
> name = obj.substance.name
<http://obj.substance.name>
> text = obj.avoid
> comment = "{0}\n{1}: {2}".format(comment, name,
text)
> comment = comment.strip()
> if comment:
> self.avoid = comment
>
> if not self.incompatibilities:
> comment = ""
> for obj in state_objs:
> if obj.incompatibilities:
> name = obj.substance.name
<http://obj.substance.name>
> text = obj.incompatibilities
> comment = "{0}\n{1}: {2}".format(comment, name,
text)
> comment = comment.strip()
> if comment:
> self.incompatibilities = comment
>
> Thanks
>
> Mike
>
>
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