WWW, E‑Governance & Internet Connectivity — IP, ISP, DNS
🌐 WWW, E‑Governance, and Internet Connectivity
This covers the essential concepts of how the Internet and the World Wide Web function, how governments leverage them, and the basic addressing and connection methods used.
I. World Wide Web (WWW) and Addressing
The World Wide Web (WWW) is an information system where resources (documents, images, videos) are identified by URLs, interlinked by hypertext, and accessed via the Internet.
Website Address and URL
The terms “website address,” “web address,
Read MoreCloud Computing, Web 2.0, and Inter-Process Communication
Cloud Computing Fundamentals
Cloud computing is a technology that allows users to store, manage, and process data over the internet instead of using local computers or physical servers.
Key Features of Cloud Computing
- Provides on-demand access to computing resources.
- Reduces the need for expensive hardware.
- Users pay only for what they use (pay-as-you-go).
- Data can be accessed from anywhere with internet connectivity.
Types of Cloud Services
- IaaS (Infrastructure as a Service): Virtual machines, storage.
Essential Concepts in Database Management, E-Commerce, and BI
Database Management Systems
DBMS Software Components
A Database Management System (DBMS) contains five important software components. One of these is the: Data Definition Subsystem.
Primary and Foreign Keys
Every primary key can also be used as a: Foreign Key (when referencing another table).
Storing Facts About Information (Metadata)
If you needed to store facts about the information you were collecting, you would use a: Data Dictionary.
Unique Identification Field
If your phone number was used in a clothing
Korn Shell Scripting, Linux Features, and Editor Basics
Korn Shell Relational Expressions
In Korn shell (and other Bourne-like shells), relational expressions are typically evaluated inside the [[ ... ]] (conditional) construct or using the test (or [) command. The operators use mnemonics for numerical comparison.
1. Numerical Comparisons in Korn Shell
(a) c ≥ d
To check if the numerical value of variable c is greater than or equal to the numerical value of variable d:
[[ $c -ge $d ]]The -ge operator stands for “greater than or equal to”.
(b) c < d
To
Read MoreHybrid Hash-Join Performance Optimization in Database Systems
Hybrid Hash-Join: Conceptual Explanation
Hybrid Hash-Join is an improved version of the standard Hash-Join algorithm that reduces disk I/O by using memory more efficiently during the join operation. It is particularly useful when:
- The build relation is larger than memory.
- Memory is still large enough to hold one or more partitions fully.
Why Use Hybrid Hash-Join?
In a normal Hash-Join:
- All partitions of the build relation are written to disk first.
- They are then read again for probing.
Hybrid Hash-Join
Read MoreFundamentals of DBMS and Database Concepts
Data, Information, Knowledge
Data – a fact that can be recorded or stored, e.g., person name, age, gender, weight, etc. Information – when data is processed, organized, structured, or presented in a given context so as to make it useful, it is called information. Knowledge – it is the appropriate collection of information.
DBMS (Database Management System)
DBMS = Database + Set of programs.
- Database – a collection of logically related data; e.g., books database in a library, student database in a university.