how the search engine works

search engine perform several activities to deliver search result:

Do you know how search engines work? There are three basic stages for a search engine: crawling – where content is discovered; indexing, where it is analysed and stored in huge databases; and retrieval, where a user query fetches a list of relevant pages

Crawling - Process of fetching all the web pages linked to a website. This task is performed by a software, called a crawler or a spider (or Googlebot, in case of Google).

Indexing - Process of creating index for all the fetched web pages and keeping them into a giant database from where it can later be retrieved. Essentially, the process of indexing is identifying the words and expressions that best describe the page and assigning the page to particular keywords.

Processing - When a search request comes, the search engine processes it, i.e. it compares the search string in the search request with the indexed pages in the database.

Calculating Relevancy - It is likely that more than one page contains the search string, so the search engine starts calculating the relevancy of each of the pages in its index to the search string.

Retrieving Results - The last step in search engine activities is retrieving the best matched results. Basically, it is nothing more than simply displaying them in the browser.

Define search engine?

A web search engine is designed to search for information on the World Wide Web and FTP servers. The search results are generally presented in a list of results and are often called hits. The information may consist of web pages, images, information and other types of files. Some search engines also mine data available in databases or open directories. Unlike Web directories, which are maintained by human editors, search engines operate algorithmically or are a mixture of algorithmic and human input.