Re: Recursive Arrays 101 - Mailing list pgsql-general

From David Blomstrom
Subject Re: Recursive Arrays 101
Date
Msg-id CAA54Z0hsXt7pmUjhUNYnqq7vXa5jUtGBFdf7BVU=jc-7j8v74A@mail.gmail.com
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In response to Re: Recursive Arrays 101  (Rob Sargent <robjsargent@gmail.com>)
List pgsql-general
Thanks for that tip, Achilleas.

On Wed, Nov 4, 2015 at 7:53 AM, Rob Sargent <robjsargent@gmail.com> wrote:
On 11/04/2015 03:03 AM, Achilleas Mantzios wrote:
Sorry for being kind of late to the party (I was in 2015.PgConf.EU !!), and not having read
most of the replies, what we have been successfully doing for this problem for our app
is do it this way :
parents int[] -- where parents stores the path from the node to the root of the tree
and then have those indexes :
btree (first(parents))
btree (level(parents)) -- length
btree (last(parents))
gin (parents gin__int_ops) -- the most important

This has been described as "genealogical tree" approach, and works very good, IMHO much better
than nested sets.

Is there a more complete description of this approach available?  By the title one might assume could be applied to populations as opposed to phylogeny (the OP's use case).  Does it deal with consanguinity?  Does it perform well going "up" the tree (which is of course branched at every level)?



--
David Blomstrom
Writer & Web Designer (Mac, M$ & Linux)
www.geobop.org

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