Comments on: The thrill of a new technology: CouchDB

By: Chiaroscuro

Chiaroscuro — Thu, 09 Apr 2009 22:24:58 +0000

I wrote the original CRM system Giovanni is talking about. It’s based on a piece of RoR software that uses a relational model to handle tag-based Notes. I also implemented a tag algebra to handle tags, metatags and such.. so that I could write things such as: “ruby -city:NY on:tomorrow” to find all events related to ruby, not taking place in NY tomorrow.

Although I tried to build nice abstractions I had to break them continuously to handle ugly performance problems. Also the queries felt unnatural, awkwardly mapping to the domain I was trying to describe. My business logic also got badly cluttered with small variations of the same code. I could refactor that only to a point..

I hope that CouchDB can provide some solution. The code is certainly much much more understandable as there is a pretty cozy paradigm fit.

We’ll let you know how it goes..

By: Mark

Mark — Tue, 31 Mar 2009 11:51:22 +0000

@emaaaa thats exactly the article we are using. I know Giovanni thinks its conservative, but for us, its a perfect transition, i.e. we are implementing a system where the previous implementation used relational data. However I believe for the client facing logic the documents are the best…

By: Giovanni Intini

Giovanni Intini — Tue, 31 Mar 2009 11:46:23 +0000

@emaaaa I read it and I really liked the article, but I think that building a document based store on top of mysql is a very conservative (too much) approach. If the right tool for a job exists, I ‘m happy to use it.

It worked for them though so I can’t say anything

By: emaaaa

emaaaa — Tue, 31 Mar 2009 08:18:31 +0000

i feel impressed reading this work:
“How FriendFeed uses MySQL to store schema-less data”
http://bret.appspot.com/entry/how-friendfeed-uses-mysql

title is self-explanatory

maybe it’s interesting in this discussion

By: Giovanni Intini

Giovanni Intini — Mon, 30 Mar 2009 21:10:53 +0000

@bennyb it’s used to return an array of all the people tagged with a certain tag in a single document.

By: bennyb

bennyb — Mon, 30 Mar 2009 19:03:41 +0000

What is the point of the reduce function in your example?

// reduce
function(keys, values, rereduce) {
return values;
}

By: dm

dm — Mon, 30 Mar 2009 15:33:36 +0000

This looks like something that’s useful on smaller projects where a relational db would be overkill. however i don’t think it would be appropriate in an enterprise environment.

also, data storage is a hard problem, people. this is no one-solution-that-fits-all.

By: jay

jay — Mon, 30 Mar 2009 15:16:05 +0000

@jkf
“Though it is usually better for less apps than I see it advocated for: basically anything where you care about the data’s integrity.”

This is a false choice. Data integrity is not, and should not, be an either or proposition for any serious app.

By: Reggie

Reggie — Mon, 30 Mar 2009 15:13:59 +0000

I Think sometimes flexibility is what we need and relational databases are not the right solution in some cases.

Think at this case. You wanna map all of your devices in your home. In this scenario you can have different devices, and each one can have different properties. Flexibility in this case is necessary, as you can’t really decide before which fields you will have.

By: JKF

JKF — Mon, 30 Mar 2009 15:13:36 +0000

Well I wish you all the luck with that transition, I really hope it works for you, but the best I can do is warn you: What feels like flexibility now in getting rid of the impedance mismatch in your “store” will constrain your ability to organize, aggregate, and adapt your data in the future.

Even for web2.0 companies, your life will be your data, and thinking about how you deal with data first, instead of how to just store the artifacts of your programming is how you will build lasting value. Your code no matter how lovely will rot and be thrown away in some future version, but your data should be forever in an information organization. Never forget that.

Best of luck, and hopefully be aware of what you’re giving up while moving forward into that schema-less world.