On 02/02/2009, at 12:22 AM, Martin Scholl wrote:
What worries me most, is that I am still unsure in how to differ
between
design docs and indexing schemes, and when to use which
infrastructure.
Applied to the doc-relationship example you gave: how should
"intermediate reults" of the dag processing be treated? As documents?
Should they be put into view functions? Should views be able to hint,
which indexing scheme is to be used? Depending on the index type,
indexing and doc / view-processing can become inherently coupled and
complex. Is this still CouchDB then?
No sure if this is exactly what you're talking about, but the way I
was thinking (which I picked up from GeoCouch) was to have design docs
that define no couch view, that allow you to configure the external
e.g. in my case, which was for returning the TC of user/role/
permissions graphs, that might look like this:
{
"_id": ...,
"_rev": ...,
transitive_closure_generator: {
"User": { "from": "_id", "to": "[roles]" },
"Role": { "from": "_id", "to": "[permissions]" },
}
}
Then, in my external I process such docs in my update-loop to generate
the configuration of the external i.e. I monitor changes to design
docs with a 'transitive_closure_generator' element, obviously caching
and persisting that configuration. You also need to catch design docs
updates that remove that element, and the deletion of monitored docs
as well.
Because I use CouchRest, I can use the 'couchrest-type' key that it
inserts to identify which document's fields I need to process e.g.
'User'/'Role'.
As an aside, it might be nice if you could use that doc to define the
endpoint for your externals, so you could completely simulate a built-
in view. Putting external configuration into design docs isn't good
idea but maybe it could be indirect e.g.
{
"_id": 'my_design',
"_rev": ...,
transitive_closure_generator: { ... }
externals: {
view_name: 'tc',
external: <the id of the external mapping in the .ini>
}
}
which would then allow you to access your external via '_view/
my_design/tc'. External views mapped like this would need to adhere to
the view contract e.g. params etc.
Antony Blakey
--------------------------
CTO, Linkuistics Pty Ltd
Ph: 0438 840 787
Always have a vision. Why spend your life making other people’s dreams?
-- Orson Welles (1915-1985)
