On Sep 16, 2009, at 5:42 PM, Chris Anderson wrote:
On Wed, Sep 16, 2009 at 3:04 PM, <[email protected]> wrote:
Author: jchris
Date: Wed Sep 16 22:04:18 2009
New Revision: 815984
URL: http://svn.apache.org/viewvc?rev=815984&view=rev
Log:
include_docs now take an _id (as well as a _rev) in the emitted
value, to load docs other than the one doing the emitting. This
means you can have one doc list a set of other docs to load in a
single query. Enjoy!
In Governator voice: "It's not a JOIN."
But you can use it if you have a doc like:
{"_id":"my-outline",
"other_docs":["docid,"other-docid"]
}
and then a view like
function(doc) {
for (var i=0; i < doc.other_docs.length; i++) {
emit([doc._id, i], {"_id" : doc.other_docs[i]}
};
}
and then you will have an ordered list of the other docs available in
a view query (with include_docs) You can also specify the other docs
_rev if you want -- if it's not available it comes up as null in the
feed.
Of course, the usual include_docs performance caveats apply, but this
time we get a feature out of it!
Chris
I'm thinking that this may be sufficient to address the use case
described in http://wiki.apache.org/couchdb/
Forward_document_references. I was uneasy about that proposal since
it strongly favored using one document per entity when that model may
not be the appropriate partitioning scheme, but I never bothered
putting my thoughts down since it looked like it wasn't going any
where fast.
This appears to be better, but it seems to be assigning some magic
behavior to the second argument so it specifies both the value. Was
there previous discussion or a bug report filed on this that I missed?
I'm thinking it would be cleaner to support an optional 3 argument to
emit with { _id:"", _rev:"" }? The current two argument emit() would
be the equivalent of emit(key, value, { _id:doc._id, _rev:doc.rev}).
