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Date: Fri, 12 Dec 2008 08:12:51 -0800
From: "Adam Wolff" <awolff@gmail.com>
To: couchdb-user@incubator.apache.org
Subject: DAG on couch
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Hi everyone,
I'm just getting started with CouchDB and I'm really excited about it. I'm
working with a directed acyclic graph, and I'd like to be able to
efficiently
retrieve graph chunks with a single query.

So conceptually, my data looks like this

doc1: {content: ..., ancestor: null}
doc2: {content: ..., ancestor: "doc1"}
doc3: {content: ..., ancestor: "doc2"}
doc4: {content: ..., ancestor: "doc3"}
doc5: {content: ..., ancestor: "doc3"}


Long runs of singly linked ancestors will be common; branches (e.g. after
doc3
in the example above) will be less common but not rare.

I get how you can use couch to retrieve a primary key and foreign key at the
same time (through view collation) but I'm wondering if there's a clever way
to
do this recursively.

If I could pull depths of 5 nodes or so at a time, that'd be fine. I can
always
go back for more if I need it. I can imagine a few hacky solutions, like
retaining a list of ancestors, but that it makes it pretty much impossible
to
reorder the graph.

Is there a clever solution I'm missing?

Thanks in advance,
A

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