Working of search engine

Good Morning students
 In today's session, we will be learning about Search engines and their working.
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The Google meet link for today is  

meet.google.com/ryj-apdc-okt

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WORLD WIDE WEB(WWW) 

• is a store house with an enormous amount of information.
• Locating the exact information is very important.
• Search engine is needed for this.

SEARCH ENGINES

• is a tool that is designed to search for 
• information or 
• documents 
• specified by KEYWORDS on the World Wide Web.
• Examples: Bing, Google, Ask, Yahoo, and MSN.
• Google tops them all 

HOW SEARCH ENGINE WORKS

• All search engines work in the same way.
• This consists of 3 major steps
• WEB CRAWLING
• CREATING AND INDEX
• SEARCH FOR KEYWORDS

WEB CRAWLER:

• searches the websites and selects pieces of information  from various websites.
• This is the first part of the search engine.
• Also known as SPIDER or a ROBOT
• This spider crawls or jumps from one web page to the other following all links looking for updated pages.
• This process is called WEB CRAWLING.
• Is done on regular basis to have updated information.

CREATING AND INDEX:

• In the second step the, an index of the data and their location is created.
• Everything that the spider finds will be stored in the second part called the INDEX.
• The INDEX is a massive catalogue sort of structure that stores a copy of the information and its location
• Each time the web page is changed, this index will also periodically store itself.
• The search engine builds up its own database of the information available on the web pages.

SEARCH FOR KEYWORDS:

• Search for keyword in the index is done.
• This part of a search engine is the actual search software.
• This will surf through the millions of pages in the search engine's database or index and try to match the keywords that the user entered into the search query box.
• Once it finds the matches, it will display them to the user according to their relevance.

USING A SEARCH ENGINE:

     To search any information on the web, follow the given steps:

• Open your browser
• Open the popular search engine, Google, by typing www.google.co.in
• Type a keyword in the search box and press Enter key. In the example "Internet" .
• You will be given a long list of all the websites related to the keyword you typed.
• Click on any of the links you think is most suited to your needs.
• The relevant web page will be displayed.

A good search engine will result in relevant data

It will yield the result faster.

Google, yahoo, MSN are popular search engines.

SEARCHING TIPS AND TRICKS:

1. OR Operator
• Use OR operator to choose one of the two terms.
• Eg. Music OR Dance
2. AND operator
• To search for results that contain both the terms
• Eg. Music AND Dance.
3. NOT operator
•  To search for web pages that DO NOT contain the specified term.
• Eg. Music NOT classical
4. The "  " quotation sign
• To search for terms as it is in the web page results.
• Eg. "Rock Music"
5. The + sign
• Use + sign before a search term when you require that the term appears in the web page results.
•  Eg. To search for results that must contain music and may also contain Dance

                     Music+Dance

     6. The - minus sign

• Use - sign before a search term when you require that the term  does not appear in the web page results.
•  Eg. To search for results that must contain Indian classical dance but not Kathak, use the following

 "Indian Classical Dance"- Kathak