Re: [SQL] Trees in SQL (again)

>
> I'm trying to implement set model of trees in SQL and I found a problem:
>
> How to find first level children of parent?
>
> For this structure (with left and right set values):
>
> 1 Jerry 10
> |
> -------------------
> | |
> 2 Bert 3 4 Chuck 9
> |
> ------------
> | |
> 5 Donna 6 7 Fred 8
>
> The question is: Who is first level child of Jerry?
> The answer should produce:
> Bert
> Chuck

The children must know. It is the same situation as in the
unix filesystem. And that's why there is a '..' entry in
every directory, pointing to the inode of the parent.

So each node must have a field identifying it's parent. The
root node (Jerry) might simply point back to itself to
identify that.

Jan

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