> Another way to do this is:
>
> Items
> -----
> ItemID Integer
>
> Links
> -----
> ParentID --> Items.ItemID
> ChildID --> Items.ItemID
>
>
> This has no NULLs ...

Hello Martijn,

thank you for your kind reply. I'm not sure how to store more ChildID
links, when there's 1:n - parent:child relationship.

Thank you for your reply.