Re: Encoding materialized path in an atomic value.

"Hugo Kornelis" <hugo_at_pe_NO_rFact.in_SPAM_fo> wrote in message news:4eq8j1pvan8qnmo7sh8235eamtraqmae41_at_4ax.com...
> On Fri, 23 Sep 2005 20:24:42 GMT, David Cressey wrote:
>
> (snip)
>>Anyway, a common encoding technique for ancestor's is to assign a number
>>for each ancestor, according to a binary pattern, with one for a father
>>and zero for a mother.
>>
>>Thus your ancestor number 23 is as follows: writing the number in binary,
>>but showing the bits backwards (LSB first): 11101
>>
>>This means that ancestor 23 is you father's father's father's mother's
>>father.
>
> Hi David,
>
> Maybe I'm missing something here? What would the code be for your
> father's father's father's mother's father's mother? If I understand the
> method correctly, the binary LSB-first notation would be 111010. And
> that would also be 23 in decimal.

The encoding would be unambiguous if the binary string length were specified as well, although I do not see what advantage 100010 has in comparison to FMMMFM except probably being more compact.

>
>>23 is, I think we will all agree "atomic" or "simple" enough so that it
>>can be stored in a single value.
>
> Yeah. But in this case, it lacks unambiguity.
>
> Best, Hugo
> --
>
> (Remove _NO_ and _SPAM_ to get my e-mail address)
Received on Sat Sep 24 2005 - 05:15:36 CEST