[
https://issues.apache.org/jira/browse/COUCHDB-2176?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13914949#comment-13914949
]
Adam Kocoloski commented on COUCHDB-2176:
-----------------------------------------
It's been discussed a number of times on the dev@ list dating all the way back
to 2009, but I'm not aware of any pre-existing JIRA ticket. It's a significant
effort; some good news is that the work [~benoitc] did on adding sequence
indexes to views is quite likely foundational for this feature.
> Map/Reduce views within views
> -----------------------------
>
> Key: COUCHDB-2176
> URL: https://issues.apache.org/jira/browse/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 have.
--
This message was sent by Atlassian JIRA
(v6.1.5#6160)
