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From Mister Donut <lady.do...@gmail.com>
Subject Re: The Blog
Date Mon, 09 Feb 2009 10:28:57 GMT
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.

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