Articles by Gerd Wagner (Articles: 15, Technical Blogs: 27, Tip/Tricks: 2)

Articles: 15, Technical Blogs: 27, Tip/Tricks: 2

• Articles
• Technical Blogs
• Tips and Tricks
• Reference Articles
• Projects

Average article rating: 4.84

	Integrity Constraints and Data Validation 3 Apr 2014   Updated: 28 Nov 2015   Rating: 4.73/5    Votes: 15   Popularity: 5.56 Licence: CPOL    Views: 41,550     Bookmarked: 24   Downloaded: 0 Please Sign up or sign in to vote. What are the most important types of integrity constraints to be checked in any data management app?
Internet of Things
	iotduino takes JavaScript to the land of microseconds 10 Dec 2014   Updated: 10 Dec 2014   Rating: 5.00/5    Votes: 6   Popularity: 3.89 Licence: CPOL    Views: 17,000     Bookmarked: 9   Downloaded: 0 Please Sign up or sign in to vote. In this article, we describe how to develop IoT apps with Node/JavaScript for the Arduino-compatible PCDuino. We take JavaScript to the land of microseconds where a digitalWrite operation takes 6-7 microseconds and a digitalRead operation takes 4-5 microseconds.
Arduino	Optimize Arduino Memory Usage 28 Jul 2015   Updated: 28 Jul 2015   Rating: 4.88/5    Votes: 15   Popularity: 5.73 Licence: CPOL    Views: 49,939     Bookmarked: 14   Downloaded: 0 Please Sign up or sign in to vote. When working with embedded devices, RAM (random access memory) is one of the most valuable and limited resource of the system. The focus of this article is on the RAM usage optimization for Arduino MCUs, but the same principle applies to many other embedded devices.
Programming Languages
Javascript	JavaScript Summary 2 Jul 2015   Updated: 25 Jul 2016   Rating: 4.96/5    Votes: 126   Popularity: 10.38 Licence: CPOL    Views: 164,635     Bookmarked: 191   Downloaded: 0 Please Sign up or sign in to vote. A short summary of JavaScript's main features, including a discussion of the different kinds of JS objects, basic data structures, functions as first class citizens, and code patterns for implementing classes. "In over 20 years programming this is the single best overview of any language ever!"
	Managing Key-Value Stores with JavaScript's LocalStorage API 14 May 2019   Updated: 14 May 2019   Rating: 5.00/5    Votes: 1   Popularity: 0.00 Licence: CPOL    Views: 5,983     Bookmarked: 5   Downloaded: 0 Please Sign up or sign in to vote. We show how to deal with key-value pairs and how to manage a key-value store using JavaScript's localStorage API.
Web Development
ASP.NET	Really Understanding Association, Aggregation, and Composition 26 Feb 2015   Updated: 6 Apr 2015   Rating: 4.92/5    Votes: 22   Popularity: 6.40 Licence: CPOL    Views: 34,341     Bookmarked: 41   Downloaded: 0 Please Sign up or sign in to vote. This is an alternative for "Understanding Association, Aggregation, and Composition", correcting three flaws, one in each of the three explanations, contained in the original article.
HTML	JavaScript Front-End Web App Tutorial Part 3: Dealing with Enumerations 21 May 2015   Updated: 2 Jul 2015   Rating: 4.55/5    Votes: 8   Popularity: 4.10 Licence: CPOL    Views: 23,771     Bookmarked: 16   Downloaded: 191 Please Sign up or sign in to vote. This tutorial shows how to build a plain JS web app where model classes have enumeration attributes, which have to be rendered in the HTML user interface with selection lists, radio button groups and checkbox groups.
	AngularJS Front-End App with Cloud Storage Tutorial Part 1: Building a Minimal App in Seven Steps 9 Sep 2015   Updated: 9 Sep 2015   Rating: 5.00/5    Votes: 13   Popularity: 5.57 Licence: CPOL    Views: 37,880     Bookmarked: 28   Downloaded: 291 Please Sign up or sign in to vote. Learn how to build a front-end web application with minimal effort in seven steps, using the AngularJS framework and the cloud storage service Parse.com.
	JavaScript Front-End Web App Tutorial Part 1: Building a Minimal App in Seven Steps 2 Apr 2014   Updated: 1 Dec 2015   Rating: 4.87/5    Votes: 53   Popularity: 8.36 Licence: CPOL    Views: 352,842     Bookmarked: 120   Downloaded: 5,532 Please Sign up or sign in to vote. Learn how to build a front-end web application in plain JavaScript with minimal effort. Do not use any (third-party) framework or library, such as jQuery or Angular, which create black-box dependencies and overhead, and prevent you from learning how to do it yourself.
	Simplifying the Definition of Constructor-Based Classes with cLASSjs 29 Dec 2015   Updated: 18 Jan 2016   Rating: 4.43/5    Votes: 4   Popularity: 2.67 Licence: CPOL    Views: 22,051     Bookmarked: 1   Downloaded: 52 Please Sign up or sign in to vote. cLASSjs is a small (2 kB) JS library for defining constructor-based classes with prototype-based method inheritance like so: Student = new cLASS({ Name:"Student", supertypeName:"Person", properties:..., methods:...}).
	JavaScript Front-End Web App Tutorial Part 4: Managing Unidirectional Associations 25 Feb 2015   Updated: 23 Mar 2015   Rating: 4.53/5    Votes: 9   Popularity: 4.32 Licence: CPOL    Views: 18,512     Bookmarked: 12   Downloaded: 169 Please Sign up or sign in to vote. Learn how to develop front-end web apps with unidirectional associations between model classes, such as the associations that assign authors and publishers to books. While in many other tutorials, associations are only superficially discussed, if at all, this article provides an in-depth explanation
	JavaScript Front-End Web App Tutorial Part 2: Adding Constraint Validation 10 Apr 2014   Updated: 25 Jun 2015   Rating: 4.89/5    Votes: 18   Popularity: 6.01 Licence: CPOL    Views: 46,925     Bookmarked: 46   Downloaded: 689 Please Sign up or sign in to vote. Learn how to develop front-end web apps with responsive (HTML5) constraint validation using plain JavaScript. Do not use any framework/library (like jQuery or Angular), which just create black-box dependencies and overhead, and prevent you from learning how to do it yourself.
	Declarative and Responsive Constraint Validation with mODELcLASSjs 27 Oct 2014   Updated: 24 Aug 2016   Rating: 4.94/5    Votes: 7   Popularity: 4.17 Licence: CPOL    Views: 21,541     Bookmarked: 8   Downloaded: 105 Please Sign up or sign in to vote. Avoiding boilerplate code for constraint validation in a JavaScript front-end web app by using the model-based framework mODELcLASSjs
	Building a Video Chat Web App with WebRTC 22 Jan 2016   Updated: 21 Dec 2016   Rating: 4.95/5    Votes: 38   Popularity: 7.71 Licence: CPOL    Views: 268,799     Bookmarked: 57   Downloaded: 10,523 Please Sign up or sign in to vote. WebRTC (Web Real Time Communication) is a new web standard that allows peer-to-peer communication between browsers for high-quality RTC apps. In our tutorial, we show how to use it for building a video chat app.
	Java Back-End Web App Tutorial Part 1: Building a Minimal App in Seven Steps 19 Nov 2015   Updated: 20 Nov 2015   Rating: 5.00/5    Votes: 10   Popularity: 4.77 Licence: CPOL    Views: 170,717     Bookmarked: 20   Downloaded: 1,666 Please Sign up or sign in to vote. Learn how to build a Java back-end web application with minimal effort, using Java Server Faces (JSF) as the user interface technology, the Java Persistence API (JPA) for object-to-storage mapping, and a MySQL database.

Average blogs rating: 4.74

	Why Are Associations So Difficult to Understand, Not Just for Developers? [Technical Blog] 21 Nov 2014   Updated: 6 Apr 2015   Rating: 4.75/5    Votes: 5   Popularity: 3.32 Licence: CPOL    Views: 14,090     Bookmarked: 11   Downloaded: 0 Please Sign up or sign in to vote. Why are associations so difficult to understand, not just for developers?
	Understanding Application Architectures [Technical Blog] 24 Aug 2016   Updated: 2 Sep 2016   Rating: 4.72/5    Votes: 9   Popularity: 4.51 Licence: CPOL    Views: 14,690     Bookmarked: 11   Downloaded: 0 Please Sign up or sign in to vote. We discuss the widely used, but ill-defined MVC architecture metaphor, and point out that the model classes should be decoupled from the storage component.
All Topics
	What does it need to be not only a good coder, but become a great app developer? [Technical Blog] 1 Oct 2015   Updated: 1 Oct 2015   Rating: 4.21/5    Votes: 8   Popularity: 3.81 Licence: CPOL    Views: 4,601     Bookmarked: 6   Downloaded: 0 Please Sign up or sign in to vote. If you want to become a great app developer, it's not sufficient that you master your favorite programming technologies. It's essential that you understand all basic concepts and techniques, not just in programming, but also in information management.
Database Development
	Storing Database Tables in JavaScript's Local Storage [Technical Blog] 20 Jan 2015   Updated: 20 Jan 2015   Rating: 4.89/5    Votes: 8   Popularity: 4.42 Licence: CPOL    Views: 24,240     Bookmarked: 14   Downloaded: 0 Please Sign up or sign in to vote. Storing database tables in JavaScript's Local Storage
	CRUD Operations with IndexedDB - Part 1: Creating and Clearing a Database [Technical Blog] 24 Jan 2018   Updated: 24 Jan 2018   Rating: 5.00/5    Votes: 2   Popularity: 1.51 Licence: CPOL    Views: 11,051     Bookmarked: 8   Downloaded: 0 Please Sign up or sign in to vote. How to create and clear an IndexedDB database keeping all code in a single HTML file. Creating an IndexedDB database means first creating an empty database, and then adding records to its empty tables (or "object stores").
Internet of Things
	WoT with Arduino for Beginners: Part 2 - Connecting to the Real World via Sensors [Technical Blog] 17 Apr 2016   Updated: 18 Apr 2016   Rating: 5.00/5    Votes: 12   Popularity: 5.40 Licence: CPOL    Views: 28,206     Bookmarked: 19   Downloaded: 288 Please Sign up or sign in to vote. Learn how to develop Arduino-based apps for the Web of Things (WoT). This second part of a series of tutorials shows how to read analog and digital sensors with the help of Arduino.
	WoT with Arduino for Beginners: Part 1 - Mastering the RGB LED [Technical Blog] 7 Apr 2016   Updated: 22 Apr 2016   Rating: 4.80/5    Votes: 23   Popularity: 6.54 Licence: CPOL    Views: 46,983     Bookmarked: 40   Downloaded: 296 Please Sign up or sign in to vote. Learn how to develop Arduino-based apps for the Web of Things (WoT). This first part of a series of tutorials shows the basics of an Arduino program (known as a "sketch") and provides a quick introduction to some electronic components, including resistors, RGB LEDs and LEDs in general.
	Architectures for the Web of Things [Technical Blog] 14 Oct 2015   Updated: 30 Dec 2015   Rating: 4.60/5    Votes: 4   Popularity: 2.77 Licence: CPOL    Views: 18,563     Bookmarked: 13   Downloaded: 0 Please Sign up or sign in to vote. Architectures for the Web of Things
Arduino	Arduino Software Reset [Technical Blog] 23 Jul 2015   Updated: 23 Jul 2015   Rating: 4.60/5    Votes: 9   Popularity: 4.39 Licence: CPOL    Views: 103,378     Bookmarked: 13   Downloaded: 0 Please Sign up or sign in to vote. Three easy ways to programmatically reboot/reset an Arduino MCU.
	PRODINo: Home Automation with ESP8266 based WiFi Control [Technical Blog] 4 Dec 2016   Updated: 4 Dec 2016   Rating: 5.00/5    Votes: 7   Popularity: 4.23 Licence: CPOL    Views: 20,621     Bookmarked: 15   Downloaded: 482 Please Sign up or sign in to vote. Home Automation is made simple for everyone, with the industrial grade PRODINo ESP8266 based module. It can be programmed with the Arduino IDE and allows to control (ON/OFF switch) mains (110-240 VAC) powered devices such as light bulbs, water pumps, cafe machines or garage doors.
	Identifying the Arduino Microcontroller Type [Technical Blog] 22 Jul 2015   Updated: 22 Jul 2015   Rating: 4.60/5    Votes: 5   Popularity: 3.22 Licence: CPOL    Views: 9,040     Bookmarked: 6   Downloaded: 0 Please Sign up or sign in to vote. Learn how to identifying the Arduino microcontroller type by simply using C/C++ code.
Raspberry-Pi	JavaScript-Based IoT/WoT Development with the ESP8266 [Technical Blog] 14 Oct 2016   Updated: 20 Oct 2016   Rating: 4.48/5    Votes: 8   Popularity: 4.04 Licence: CPOL    Views: 51,006     Bookmarked: 19   Downloaded: 340 Please Sign up or sign in to vote. As opposed to the less powerful Arduino, the competitively priced and WiFi-enabled ESP8266 supports the Web-of-Things (WoT) since it can be programmed in JavaScript.
Programming Languages
C	WoT with Arduino for Beginners: Part 3 - Connecting to the Internet via WiFi [Technical Blog] 3 May 2016   Updated: 3 May 2016   Rating: 5.00/5    Votes: 11   Popularity: 5.21 Licence: CPOL    Views: 27,602     Bookmarked: 15   Downloaded: 358 Please Sign up or sign in to vote. In this multi-part tutorial we show how to develop Arduino-based apps for the Web of Things (WoT). This third part shows how to set up a connection between an Arduino and the Internet via a WiFi network and use HTTP(S) to send data to a free cloud service like ThingSpeak.
ECMAScript 6	Using JavaScript's Implicit Setters and Getters [Technical Blog] 24 May 2017   Updated: 24 May 2017   Rating: 5.00/5    Votes: 3   Popularity: 2.39 Licence: CPOL    Views: 7,891     Bookmarked: 3   Downloaded: 0 Please Sign up or sign in to vote. Already available from ES5.1 (and even supported by IE 9), JavaScript's set and get methods have not been used very widely. Their main use case is the implementation of a best practice in OOP.
Javascript	AngularJS Does Not Have a Model: It's not MV*, But Rather VM* [Technical Blog] 11 Feb 2015   Updated: 11 Feb 2015   Rating: 5.00/5    Votes: 1   Popularity: 0.00 Licence: CPOL    Views: 9,010     Bookmarked: 2   Downloaded: 0 Please Sign up or sign in to vote. AngularJS does not have a Model: It's not MV*, But rather VM*
	Defining and Using Classes in JavaScript [Technical Blog] 16 Jul 2015   Updated: 16 Jul 2015   Rating: 5.00/5    Votes: 1   Popularity: 0.00 Licence: CPOL    Views: 7,201     Bookmarked: 2   Downloaded: 0 Please Sign up or sign in to vote. The concept of a class is fundamental in object-oriented programming. Objects instantiate (or are classified by) a class. A class defines the properties and methods (as a blueprint) for the objects that instantiate it.
	Expressing Date/Time Information with the <time> Element [Technical Blog] 29 Jan 2015   Updated: 29 Jan 2015   Rating: 4.60/5    Votes: 3   Popularity: 2.19 Licence: CPOL    Views: 10,650     Bookmarked: 3   Downloaded: 0 Please Sign up or sign in to vote. Using the HTML5 element allows to express a human-readable date or a timestamp in a web page, and annotate it with a machine-readable date/time value that can be extracted and processed by applications.
	Asynchronous Programming in JavaScript [Technical Blog] 6 Jul 2021   Updated: 6 Jul 2021   Rating: 5.00/5    Votes: 2   Popularity: 1.51 Licence: CPOL    Views: 5,101     Bookmarked: 4   Downloaded: 0 Please Sign up or sign in to vote. The evolution of asynchronous programming in JavaScript: callbacks, promises, async/await
UML	Representing Information Models as RDF and OWL Vocabularies [Technical Blog] 16 Aug 2017   Updated: 16 Aug 2017   Rating: 0.00/5    Votes: 0   Popularity: 0.00 Licence: CPOL    Views: 5,572     Bookmarked: 1   Downloaded: 0 Please Sign up or sign in to vote. How to represent information models as RDF and OWL vocabularies, and how to embed simple meta-data statements (annotations) in web documents.
Reactive
	What Is Reactive Programming and How Does It Work? [Technical Blog] 18 Jul 2016   Updated: 18 Jul 2016   Rating: 5.00/5    Votes: 1   Popularity: 0.00 Licence: CPOL    Views: 7,842     Bookmarked: 2   Downloaded: 0 Please Sign up or sign in to vote. Reactive programming and how it works
Structures
	JavaScript Supports Four Types of Basic Data Structures [Technical Blog] 4 Mar 2015   Updated: 4 Mar 2015   Rating: 4.00/5    Votes: 8   Popularity: 3.61 Licence: CPOL    Views: 9,083     Bookmarked: 2   Downloaded: 0 Please Sign up or sign in to vote. The four types of basic data structures supported by JavaScript are: array lists, maps, records and JSON tables.
Web Development
	Enumerations and Enumeration Attributes in JavaScript [Technical Blog] 18 Feb 2015   Updated: 18 Feb 2015   Rating: 4.90/5    Votes: 6   Popularity: 3.81 Licence: CPOL    Views: 17,212     Bookmarked: 4   Downloaded: 0 Please Sign up or sign in to vote. Enumerations and Enumeration Attributes in JavaScript
	What's the Difference Between a JavaScript Object and a UML/Java Object? [Technical Blog] 17 Nov 2014   Updated: 17 Nov 2014   Rating: 4.33/5    Votes: 2   Popularity: 1.30 Licence: CPOL    Views: 10,571     Bookmarked: 2   Downloaded: 0 Please Sign up or sign in to vote. Difference between a JavaScript object and a UML/Java object
HTML	Learn How to Make ES6 Promises with Executable Examples [Technical Blog] 17 Feb 2016   Updated: 31 Jan 2017   Rating: 5.00/5    Votes: 9   Popularity: 4.77 Licence: CPOL    Views: 14,621     Bookmarked: 12   Downloaded: 95 Please Sign up or sign in to vote. While many new JavaScript features of ES6 (=ES2015) are still (in 2016!) not available in all important web browsers, the promising new feature of a JavaScript "promise" has arrived. This tutorial shows how to use it.
	The Most Important New JavaScript Elements for Basic Programming [Technical Blog] 24 Apr 2020   Updated: 24 Apr 2020   Rating: 5.00/5    Votes: 4   Popularity: 3.01 Licence: CPOL    Views: 6,740     Bookmarked: 6   Downloaded: 0 Please Sign up or sign in to vote. The most important new language elements of JavaScript for basic programming
	Creating HTML Tables with JavaScript/DOM Methods [Technical Blog] 6 Oct 2015   Updated: 6 Oct 2015   Rating: 3.63/5    Votes: 8   Popularity: 3.28 Licence: CPOL    Views: 24,401     Bookmarked: 6   Downloaded: 0 Please Sign up or sign in to vote. The proper way of creating an HTML table with JavaScript and inserting it into the HTML body element is using the DOM methods insertRow and insertCell.
HTML5	Drag&Drop HTML5/JS API Summary [Technical Blog] 25 Oct 2017   Updated: 25 Oct 2017   Rating: 5.00/5    Votes: 6   Popularity: 3.89 Licence: CPOL    Views: 11,322     Bookmarked: 3   Downloaded: 0 Please Sign up or sign in to vote. The HTML specification defines an event-based drag-and-drop (D&D) mechanism, which is supported by all current major browsers (including IE11 and iOS/Safari), except on Android. We show the minimum setup for a working D&D operation.

Average tips rating: 5.00

Programming Languages
Javascript	Web Development Pitfall No.1: Confusing a DOM Collection with a JS Array [Tip/Trick] 10 Dec 2015   Updated: 10 Dec 2015   Rating: 5.00/5    Votes: 5   Popularity: 3.49 Licence: CPOL    Views: 7,820     Bookmarked: 4   Downloaded: 0 Please Sign up or sign in to vote. Don't confuse a DOM collection with a JS array: Array functions, such as the forEach looping method, cannot be applied to a DOM collection!
	Dropping a DOM Node Without Consulting Its Parent [Tip/Trick] 12 Jul 2018   Updated: 12 Jul 2018   Rating: 5.00/5    Votes: 1   Popularity: 0.00 Licence: CPOL    Views: 4,820     Bookmarked: 1   Downloaded: 0 Please Sign up or sign in to vote. How to drop a DOM node without consulting its parent

Average reference rating:

No reference articles have been posted.

Average project rating:

No projects have been posted.

Gerd Wagner

Instructor / Trainer

 Germany

Researcher, developer, instructor and cat lover.

Co-Founder of web-engineering.info and the educational simulation website sim4edu.com.