The Functional Database [video] (opens in new tab)

When I'm in a rush for a tldr, I want to flick through a few slides and move on with browsing something else. But, there are a lot of times that I'm not in a rush. When I'm taking a walk or riding the bus, an MP3 of a presentation is a great way to have someone slowly explain an idea that I'm interested in -but not enough to actively concentrate on researching.

Relaxing at home on the couch is another time that I'm not in a rush. I've largely replaced evening TV time with watching presentations on various topics. InfoQ is perfect for that. I get to have an expert take an hour to carefully explain a topic that I'm only tangentially interested in while I semi-nap on my couch after dinner with a beer. This has become a low-effort means for me to gain a high-level understanding of a broad range of topics that I wouldn't otherwise have the time or willpower to sit down and actively study.

if you create an account on infoq, you're able to download the slides.

That's because agile provides hype to everyone in the company, not just developers. Every single agile consultant I've met was a mediocre programmer at best.

What rich says, on the other hand, is pure gold as you said. But it needs to be understood before its value is seen.

It's hard to sell to the manager who has no clue what all of this means, even harder to compare the tradeoffs with their current approach.

I know very well who Rich is, but I don't know (and don't want to know) any of the "agile" proponents.

> It surprises and disappoints me that he is not as well known nor revered as the agile craftsmanship peddlers.

Actually, he is better known than all those guys selling snake oil.

Is three ok? Using my limited experience playing with Datomic:

A functional DB replaces a "row" that only holds the current state of the world with a list of timestamped "facts" that can represent either the present or any point in the past.

Instead of simply recording "Bob's favorite food is pizza," we record that "'Bob's favorite food is pizza' was added at Time X." If Bob decides his favorite food is now ice cream, we record that "'Bob's favorite food is ice cream' was added at Time Y." At any time, we can query Datomic to get the current state of the world--"Bob's favorite food is ice cream." But note that we can also query Datomic to get any past state of the world. If our query is "what was Bob's favorite food 10 minutes before Time Y?" the response will be "pizza."

A regular database is like a sheet of paper that is continually erased and drawn over with a new world-state. Datomic, as a "functional database," is like a flipbook with an updated state on every page.

It means that you can write pure functions (in the functional programming sense) where one (or more) of the arguments to your function is a _database value_. In haskell the types to a query function would perhaps look like this:

    query :: Query -> DBValue -> Result

instead of

    performQuery :: Query -> IO DBConn -> IO Result

> Summary > Rich Hickey discusses how a functional database can impact the programming model, using Datomic as an example, but the principles apply to other systems using an immutable database.

It's just an advert of Datomic.

I expect it to be like this:

    (SELECT
      ("id", "login", "first_name", "last_name")
      FROM (users)
      (WHERE
        (and
          (or
            (eq "login" login)
            (eq "email" email)
          )
          (eq "password" (bcrypt password))
        )
      )
    )

(Sorry, couldn't fit more parentheses in this)

InfoQ is a pain in the ass, but if you open an account with their crappy site, as mentioned by others, you can download the presentation slides at the least. Not sure if the code mentioned will be clear, or even copy-pasteable. I know this is probably not what you are looking for, but that is probably the best you can do.