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From Gabor Ratky <rg...@rgabostyle.com>
Subject Re: About map/reduce chaining
Date Fri, 10 Jun 2011 11:02:43 GMT
Fabio, while chaining map/reduce views sounds useful, we found it easy to work around it by
updating our documents with the derived data. Subsequent views can use that derived information
in your documents. This also breaks down your chain into well-defined steps, which you can
apply to your documents by iterating over the view / _all_docs and updating them.

If you still think your problem is best solved by chaining them, look at BigCouch Chained
MapReduce Views [1] which has a somewhat restricted implementation of what you want by allowing
you to save the output of a view as documents into another document (similar as if you were
to replicate a view output into a database, something you also can't do with vanilla Apache
CouchDB).

Gabor

[1] http://support.cloudant.com/kb/views/chained-mapreduce-views

On Friday, June 10, 2011 at 12:50 PM, Robert Newson wrote:

> This feature does not exist in any release of Apache CouchDB to date.
> 
> B.
> 
> On 10 June 2011 11:25, Fabio Di Bernardini <fdb@altraqua.com (mailto:fdb@altraqua.com)>
wrote:
> > I found an old mail<http://couchdb-development.1959287.n2.nabble.com/chaining-map-reduce-in-hovercraft-td3028752.html>of
> > Chris Anderson about a patch enabling views chaining.
> > I don't find other documentations since then.
> > 
> > There are news about views chaining with latest 1.1 release?
> > 
> > Thank you.


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