On 12/13/21 7:32 PM, JORGE MALDONADO wrote:
> Hi,
>
> I have 5 tables related among them so that:
>
> * T1 is parent of T2
> * T2 is parent of T3
> * T3 is parent of T4
> * T4 is parent of T5
>
> image.png
>
> However, in some cases one table is missing so that:
>
> * T1 is parent of T3
> * T3 is parent of T4
> * T4 is parent of T5
> image.png
>
> 3 relations in total.
>
> And yet, in some cases an additional table is missing so that:
>
> * T1 is parent of T4,
> * T4 is parent of T5
>
> image.png
> The 5 tables always have the exact same fields but, of course, the
> relations are different among each case.
>
> Is there a way to design the schema so that I always have 5 tables and
> make T2 and T3 "invisible" for cases #1 and #2?
>
> Or should I consider 12 tables: 5 for case #1, 4 for case #2 and 3 for
> case #3.
>
> I will very much appreciate your feedback.
>
> Respectfully,
> Jorge Maldonado
Have you rejected using a single table with exactly the same columns +
parent_id?