Understanding Database 12 - Web Database Programming (NodeJS)

Client-server architecture

: Here, NodeJS plays the role of connecter to DB

Sequence	Web browser (Java script)	The Internet (NodeJS or other apps)	Web Server at server.com	Disk Drive at server.com(DB)
1	User enters: http://server.com
2		Look up IP address of server.com
3	Request server.com main page using IP
4			Recieve request for index page
5				Fetch index.html from hard disk
6			return index page
7	receive and display page

JavaScript 

• a simple programming language for building interactive HTML pages.
• Commonly used in the development of games and mobile applications. 
• The program can only be executed in an internet browser because it is interpreted as scripting. 
• To run and execute the code outside the browser, we can utilise Node.js.

Node.js 

• an open-source, cross-platform JavaScript runtime environment. 
• Allows JavaScript code to run outside the browser.  
• An asynchronous event-driven JavaScript runtime
• is designed to build scalable network applications.

JavaScript Variables

◉ only the letters a–z, A–Z, 0–9, the $ symbol, and the underscore (_). 

◉ First character: only a–z, A–Z, $, or _ (no numbers). 

◉ case-sensitive

◉ No limit on lengths

 

TBD