Why we add comma at the end of every URL in URL patterns in DJANGO and other thing is what is FORIEGNKEY

Answer 1

Basically URL patterns is a list. So it's not necessary to add comma after last list item. But if it's a tuple you need to append comma after last item.

Answer 2

Foreign key is basically a column in database which is used to reference primary key of other table and access the other whole tables records easily in current table. There can be many foreign keys in a table