For example: a "way" class with a name[1:n] attribute. Mapping the UML class to SQL you can get something like:
create table way ( id serial not null primary key, geom geometry, other_attribute text ) create table way_name ( way_id integer not null, name text not null, foreign key (way_id) references way (id) on update cascade on delete cascade, primary key way_name_pkey (way_id, name) )
QGIS can automatic discovers the relationship between tables and you can set up a form for the "parent" entity (way) and include a subform-relation for the names. But it seems that creating a new way is a 2-step process in QGIS because when I edit a new way I can´t set its name. I have to close/accept the form, save layers changes, open the form again and (now that the way exists in the database) set the way name. Is there any solution for 1-step new features editing?
Obviously, I can do it if no foreign key exists but I can lost the relational integrity.