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 A database schema is the blueprint or structure of a database, defining how data is organized and related. Components of database schema: 1. Tables (or relations):   Define the structure of data storage.     - Each table represents a single entity or concept (e.g., customers, orders, products).     - Tables consist of rows (or tuples) and columns (or attributes). 2. Columns (or attributes):   Define the individual elements within a table.     - Each column represents a single field or property (e.g., customer name, order date, product price).     - Columns have data types (e.g., integer, string, date) and may have constraints (e.g., primary key, foreign key). 3. Data types:  Specify the type of data stored in each column.     - Common data types include integers, strings, dates, timestamps, and Boolean values. 4. Relationships:   Define how tables are connected.     - One-to-one (1:1): One row in Table A matches one row in Table B.     - One-to-many (1:M): One row in Table A matches m

The implementation of the World Wide Web (WWW) involved several key steps and technologies: 1. HTTP (Hypertext Transfer Protocol):  Berners-Lee developed HTTP, a protocol that allows devices to communicate and share information over the internet. 2. HTML (Hypertext Markup Language):  Berners-Lee created HTML, a markup language used to structure and format content on the web. 3. URL (Uniform Resource Locator):  Berners-Lee introduced URLs, a way to address and locate web pages and resources. 4. Web Servers:  The first web server, httpd, was developed by Berners-Lee and his team to host and serve web pages. 5. Web Browsers:  The first web browser, WorldWideWeb, was developed by Berners-Lee and his team to access and display web pages. 6. Network Infrastructure:  The internet's existing network infrastructure, including TCP/IP, DNS, and packet switching, enabled the web to scale and connect globally. 7. Server-Side Scripting:  Technologies like CGI (Common Gateway Interface) and later

In CSS, pseudo-classes are used to define a state of an element based on its position, relationship with other elements, or user interaction.  They are denoted by a colon (:) followed by the pseudo-class name. Examples of pseudo-classes: 1. :hover - applied when an element is hovered over by a user 2. :active - applied when an element is being clicked or activated 3. :focus - applied when an element receives focus (e.g., when a user clicks on a form input) 4. :visited - applied to links that have been visited by the user 5. :first-child - applied to the first child element of a parent element 6. :last-child - applied to the last child element of a parent element 7. :nth-child(n) - applied to the nth child element of a parent element 8. :disabled - applied to elements that are disabled 9. :enabled - applied to elements that are enabled 10. :checked - applied to checkboxes and radio buttons that are checked Pseudo-classes allow you to apply styles to elements based on their state or posi

Packet switching is a method of transmitting data over a network by breaking it into small packets, routing each packet independently through the network, and reassembling the packets at the destination. How it works: 1. Data is divided into small packets, typically with a maximum size (e.g., 1500 bytes). 2. Each packet is given a header containing source and destination addresses, packet sequence number, and other control information. 3. Packets are transmitted over the network, potentially taking different routes. 4. Routers examine packet headers and forward them to the next hop on the path to the destination. 5. Packets may pass through multiple routers before reaching their destination. 6. The receiving device reassembles the packets in the correct order using the sequence numbers. 7. The original data is reconstructed from the packets. Packet switching allows for: - Efficient use of network resources - Flexibility and scalability - Error detection and correction - Multiplexing (m

Computer networks Computer networks refer to the interconnection of multiple computing devices for the purpose of sharing resources and information.  These networks enable communication between devices such as computers, servers, printers, routers, and other hardware components.  Classification of Computer networks Computer networks can be classified based on various criteria such as; 1. Based on Size 2. Based on Geographical Scope 3. Based on Topology 4. Based on Technologies 5. Based on Function 6. Based on Administration L et's delve a bit deeper into each classification: 1. Based on Size: - LAN (Local Area Network):   LANs typically cover a small geographic area, such as a single building, office, or campus.  They are characterized by high data transfer rates and low latency.  LANs are commonly used in homes, schools, and businesses for connecting devices like computers, printers, and servers. - MAN (Metropolitan Area Network):   MANs cover a larger geographical area than LANs,

In HTML, quotation marks can be used to wrap an element, providing visual emphasis and indicating that the enclosed content represents a quotation.  This styling technique enhances the presentation of quoted text on web pages. Setting default quotation marks: To set quotation marks to wrap an element in HTML, you can use the `quotes` CSS property along with the `content` property to specify the quotation marks to be used (the below example uses the default quotes value, so it is not mentioned as can be seen). Here's how it can be achieved: /* Define the quotation marks */ .q:before { content: open-quote; } .q:after { content: close-quote; } In this CSS: - `open-quote` represents the opening quotation mark. - `close-quote` represents the closing quotation mark. Now, you can apply the `.q` class to elements where you want to set quotation marks: <p class="q">This is a quoted text.</p> This will render as: “ This is a quoted