related objects should be included in the Columns fields

[sennierer]

currently we only include attributes of the classes in the tables, but we should include FK and M2M fields. These shouldnt be selected by default (because of the additional queries), but should be selectable via the columns field.

related to #735

[vronk]

+1 (for Frischmuth)

[b1rger]

APIS is very customizable by now, so a column with related objects (with "related" referring to objects connected by the TempTriples) this could be solved using a custom queryset together with a custom table:
Example for the Person entity:

# in `your_ontology.querysets`
# this adds the ids of related objects to the persons listed in a list view
def PersonListViewQueryset(queryset):
    ro_subquery = RootObject.objects.filter(triple_set_from_obj__subj_id=OuterRef("pk")).values("id")
    return queryset.annotate(related=ArraySubquery(ro_subquery))

# in `your_ontology.tables`
# this adds a `related` column that prints the string representation of the related objects
class PersonTable(AbstractEntityTable):
    related = tables.Column(empty_values=[])
    
    def render_related(self, record):
        rel_objs = map(str, RootObject.objects_inheritance.filter(id__in=record.related).select_subclasses())
        return ", ".join(rel_objs)

(this is only a POC, which shows related entities that are triple objects, not the other way around)

[gythaogg]

@b1rger Yes, this is fantastic - and I use it.

@sennierer talks about making these custom columns "optional" via the columns field

These shouldnt be selected by default (because of the additional queries), but should be selectable via the columns field.

At the moment only "fields" of the model are available in the columns dropdown; and the columns we define in tables appear in the view but they cannot be turned off or optionally added by selecting ín the columns field

[b1rger]

Adding to the agenda, because we might close this. It is possible to implement this in projects

[sennierer]

we make this the default behaviour with the new class based relations.
we experiment with having two dropdowns, one for attributes, one for related objects

[sennierer]

idea was to easily allow for using annotated fields in tables. there is an issue on custom table fields (#1030)