Mailing-List: contact user-help@couchdb.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@couchdb.apache.org
Received-SPF: pass (athena.apache.org: domain of lady.donut@gmail.com
 designates 72.14.204.238 as permitted sender)
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:in-reply-to:references:date:message-id:subject:from:to
         :content-type:content-transfer-encoding;
        b=a8yo2QBTaKcYj8JLbTbs7YgjvePM/abfnsRYIr9wF76mzsgZL2js6cu/Vj4T/HeG+M
         ReA2pc7pn0CPtTrtFWsKCpgJztW0RKBpuZe6/UoKw+7czsxKiXl6XODFa6STd5jsNYLk
         lqnECCi7nVnYvhKkbkxgjgbWkkHiMSZuYcPt4=
MIME-Version: 1.0
In-Reply-To: <5186956f0902082052m43546a8dmb6d9a3ebf9685034@mail.gmail.com>
References: <5186956f0902082052m43546a8dmb6d9a3ebf9685034@mail.gmail.com>
Date: Mon, 9 Feb 2009 19:28:57 +0900
Message-ID: <5186956f0902090228p5a6db266l764fde4c82b571d0@mail.gmail.com>
Subject: Re: The Blog
From: Mister Donut <lady.donut@gmail.com>
To: user@couchdb.apache.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

Hello Patrick,

I am writing down thoughts as they come.
I would appreciate if you tried to follow.
Yes, I realize storing comments inside the entry is a bad idea.
I was following an introduction to CouchDB.

> Sure, use the view to get all comments and specify count=0.
> You can get them in one query, just group comments by post_id in your map reduce query.

I don't think you understand my point.
Yes, I know. Maybe you should re-read.
You still need one lookup for every blog entry on a page.
And there is no way you can ever store the comment count inside the blog entry.

> startkey, endkey and limit.

That sounds so great. But wait. LIMIT.
I know that from SQL. It doesn't scale.
Jumping to page 1234567 of ten million. Please, no.

And you cannot, ever, group items based on a variable criteria.
For example in batches of around one hundred.
Which solves pagination.
A view cannot provide that. But again, there is no way you can "manually" do it.

> Anything!

I challenge you. Build me a counter!
No seriously.

Pick one:
GROUP BY, LIMIT, _rev to fake transactions. Uh. Oh. Hello SQL?
You know something magical that allows you to avoid _rev.

So please tell me.
What exactly can I use CouchDB for that uses its strengths,
and not weaknesses? I am honestly not trying to make a fool of anyone.
The CouchDB book seems only to justify the design choices.
The Wiki is completely unhelpful.
Every time it gets interesting.
http://wiki.apache.org/couchdb/How_to_implement_tagging
It stops. That second article, that would certainly enlighten me.
Yes, how, would you go about implementing that?

I don't see how you can make it work but by using an awful lot of merging logic.
Isn't that why you use a RDBMS in the first place?

> It's already there.

You're right, I missed that one. It's even more scary.