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From Andrius Juozapaitis <>
Subject Re: Entity Relationships in CouchDB
Date Tue, 14 Apr 2009 09:22:07 GMT
Good material Wout. I also added a reference to the page about multi
document transactions to the page, as it's kind of relevant when
modeling docs with relationships.

Andrius Juozapaitis

On Tue, Apr 14, 2009 at 6:56 AM, Jason Smith <> wrote:
> That's cool.  Some thoughts:
> 1. I changed the first sentence a little to better comply with the
> document's CC-A license.
> 2. Do you think the word "Joins" should be added somewhere to get into
> Google?  IMO this document is a better way to learn than the slightly more
> dense ViewCollation page.
> 3. Couch is different from App Engine WRT (at least) transactions and
> indexing.  Most people can use App Engine somewhat quickly because there is
> still a facility for transactions involving several objects.  (It's not a
> RDBMs but you can still do it.)  Whereas with CouchDB, the unit of atomicity
> is the document.  Speaking of documents, I'm not sure there is as big of a
> performance penalty for large Couch documents vs. large App Engine models.
>  App Engine indexes every possible combination of attributes that you might
> ever query against, but in CouchDB, you write your own indexes which, stored
> separately from the main data.  So you could have a large complex document
> (for atomic modification), but mostly read its data via various views which
> cherry-pick the important parts.
> In short, I'm not sure Couch has the same performance characteristics as App
> Engine for data.  Specifically, I would be tempted to use the "list of keys"
> method for as long as possible since you can get to your data in one view
> request.  (But I'm no expert.)
> Still, for the large portion of applications which don't have major
> performance requirements, this is a great document!  I like how it teaches
> how to do "joins" without using scary words like "view collation" and
> "map/reduce"!
> Wout Mertens wrote:
>> Hi everyone,
>> I made a stab at translating a Google document about modeling entity
>> relationships into CouchDB lingo.
>> Comments welcome.
>> Wout.
> --
> Jason Smith
> Proven Corporation
> Bangkok, Thailand

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