On Tue, Apr 28, 2009 at 09:04:18AM +0300, umut utkan wrote:
> Hi All,
>
> I am trying to create a view that can return documents according to
> a virtual hierarchy --which is stored as an attribute in the document
> like hierarchy: "products/motorcycle/dual-purpose". Is it possible to
> pass parameters to this view so that it can be used inside map/reduce
> functions? Otherwise i am going to end up with numerous views.
Not sure exactly what you want. Remember that:
(1) You can search on key prefixes. So
startkey="products/motorcycle/"&endkey="products/motorcycle/ZZZZZZZZ"
finds everything under that part of the hierarchy.
(2) you can emit multiple key/value pairs from the same document. e.g.
(untested)
//MAP
function(doc) {
if (doc.hierarchy) {
var k = doc.hierarchy.split('/');
for (var i in k) { emit(k[i], null); }
}
}
You could search this view using key="motorcycle" to get anything which has
motorcycle anywhere along the path, or
startkey="motor"&endkey="motorZZZZZZZZ"
(3) Values don't need to be strings, so you could store an already-split
array like ["products","motorcycle","dual-purpose"] if you prefer
(4) There are some more ideas at
http://wiki.apache.org/couchdb/How_to_store_hierarchical_data
HTH,
Brian.
