- What is search engine:
A software system, which is used to search documents, information and files for specified keywords, is known as search engine. Search engine allows users to search information on World Wide Web. The information may be mix of web pages, images and other type of files. Search engines are general class of programs i.e. Google, Bing, and Yahoo.
- Types of search engines:
Search engine has generally four types as following:
- Web search engine
- Local search engine
- Meta search engine
- Blog search engine
- Web search engine:
Web search engines work by using spider to fetch as many documents as possible. Many website owners use search engines to increase traffic to their website.
- Local search engine:
Local search engine is used for offline PC, CDROM or LAN searching usage.
- Meta search engine:
Meta search engine is used to gain information from various search engines and to receive combine results for better experience.
- Blog search engine:
Blog search engine is used only to index and receive search results from blogs.
- How a search engine works:
A search engine works in following process:
- Web crawling
- Web crawling:
First step of search engine is Web crawling. Web crawling is a process in which web crawler or spider systematically browses the World Wide Web, for the purpose of Web indexing.
For updating web contents, web search engine and others sites use web crawling. Web crawling is also used for web indices from other sites. Web crawlers copy all pages or information for further processing so that other users can find easily their relevant data.
Web crawler checks for standard file name, addressed to it, before sending information back to be indexed many factors, such as title, page content, headings or its Meta data.
Associating words and other definable tokens found on web pages to their domain names and HTML based fields, is known as indexing. Associations are made in public query. Public query may be in one word, index enables to find information related to query as soon as possible.
After Web crawling and indexing, search engine comes into searching process. In searching process, web search engine works according to keywords data found by web crawling and indexing.
Searching provides results relevant to queries of users. These queries may be different as following:
- Informational queries:
In this type of queries, searching provides broad content for relevant content, for which there may be number of results.
- Navigational queries:
In this type of queries, it has only a single website or web page for single entity.
- Transactional queries:
These types of queries are used to perform a particular action i.e. purchasing, downloading etc.
- Connectivity queries:
These queries are used to report on the connectivity of the indexed.