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?
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 in comment:
> if obj.ototoxic_comment:
> comment = "{0}{1}: {2}\n".format(comment,
> 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
> > 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
> > 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
> > 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
> > 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
> > text = obj.incompatibilities
> > comment = "{0}\n{1}: {2}".format(comment, name, text)
> > comment = comment.strip()
> > if comment:
> > self.incompatibilities = comment
> >
> > Thanks
> >
> > Mike
> >
> >
>
>
> --
> PLEASE NOTE OUR NEW LANDLINE IS +61 (0) 3 9034 3977
>
> Climate Pty Ltd
> PO Box 308
> Mount Eliza
> Vic 3930
> Australia +61
>
> T: 03 9034 3977
> M: 0411 704 143
>
>
>
--
You received this message because you are subscribed to the Google Groups
"Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-users+unsubscr...@googlegroups.com.
To post to this group, send email to django-users@googlegroups.com.
Visit this group at https://groups.google.com/group/django-users.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-users/54e68516-af14-41f4-a47b-0088a6ce023d%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
