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From "Nolan Lawson (JIRA)" <>
Subject [jira] [Created] (COUCHDB-2176) Map/Reduce views within views
Date Thu, 27 Feb 2014 19:19:21 GMT
Nolan Lawson created COUCHDB-2176:

             Summary: Map/Reduce views within views
                 Key: COUCHDB-2176
             Project: CouchDB
          Issue Type: Wish
      Security Level: public (Regular issues)
            Reporter: Nolan Lawson

I don't know if this has already been discussed, but often with CouchDB I've run into a situation
where a single map/reduce view couldn't quite slice my data in the way I needed.

For instance, say you want to order rows by the _value_ of an emit function, rather than the
key.  E.g., you want to emit a certain key, reduce it using {{_count}}, and then order that
output by the counts.  Currently you'd have to stuff the output of the first view into another
database (manually) and then create a new view on top of that one.

It's also pretty common for apps to have different flavors of "detail/summary" views, each
one optimized for a different page on the web site (e.g. "my inbox", "message summary", "message
with details/attachments", "message thread", etc").  In the past I've simply resorted to redundancy,
uploading the same data represented in different ways but all as documents in separate databases,
but this is a pain to manage.

Instead, I'd love it if the input of one view could simply be the output of another view.
 This would create endless flexibility and obviate the need for a lot of tinkering with the
emit values (e.g. with linked documents).  I'm not sure what the complexity would be of introducing
this into the CouchDB code, but from a user's point of view it would definitely be nice to

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