Oyem E mebinum

CQRS, Task Based UIs, Event Sourcing agh!

Posted by gregyoung on February 16, 2010

Many people have been getting confused over what CQRS is. They look at CQRS as being an architecture; it is not. CQRS is a very simple pattern that enables many opportunities for architecture that may otherwise not exist. CQRS is not eventual consistency, it is not eventing, it is not messaging, it is not having separated models for reading and writing, nor is it using event sourcing. I want to take a few paragraphs to describe first exactly what CQRS is and then how it relates to other patterns.

CQRS Command and Query Responsibility Segregation

Starting with CQRS, CQRS is simply the creation of two objects where there was previously only one. The separation occurs based upon whether the methods are a command or a query (the same definition that is used by Meyer in Command and Query Separation, a command is any method that mutates state and a query is any method that returns a value).

Gemini Agent: Core Directives and Operating Protocols

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Building Wearables Session at CampJS

Programming ESP8266 with EspruinoJS

Getting set up

The boards are flashed with Espruino. Install the CP2102 driver and Espruino IDE from the Chrome extensions store. See Anna's blog for more details.

Use the GPIO pin numbers in the code e.g. pin 4 not D2.

	/**
	* @providesModule IncrementalListView
	*/
	'use strict';

	var InteractionManager = require('InteractionManager');
	var LayoutAnimation = require('LayoutAnimation');
	var ListViewDataSource = require('ListViewDataSource');
	var RCTScrollViewManager = require('NativeModules').ScrollViewManager;
	var React = require('React');