15. Searching and Database on the Web

15.1. Introduction

In this chapter, we will find an easy way to understand the principle of search systems on the Web, including indexing and searching technologies for the traditional Database.

It is a lot of fun to browse through documents on the Web, looking at other people's home pages, learning skills by reading books on the Web, checking news, doing business and commercial, and so on. The Web becomes a more and more interesting place that many people would like to spend time on. Sometimes we want to be able to find things like we can in the library. Recent years, many search systems and search tools came up and is available to the people on the Web. But how do they work? how can we select an ideal search service that best satisfies our needs? Having these questions in mind, we will explore searching systems on the Web.

Essentially all the search services are variations of database searches. Before starting searching, we need to know where and how to search. We need create catalogies or indexes of the documents as the conventional library and traditional database do. Before indexing, we need collect information about resources or documents, determine terms to be indexed. An index is a breif description of a document. which is called a record in a database. A database is a set of records. The indexing (database) is where we start our searching. But how? Search language and search engine are used. This belongs to searching module. After a set of records ( called result set after search) is given, the documents can be transfered to us, which is called retrieval module. Briefly the major components (modules) of a search system are the following: (N. J. Yeager and R. E. McGrath, Web Server Technology, 1996)

Gather - collecting the resources to be indexed
Indexer - creating index records
Search - querying the Web. with query language and then getting information from search engine
Retrieval - retrieving resources

To understand the principle of search systems, let us examine how each of the components works and processes.

Aixiang (I Song) Yao<ayao@csgrad.cs.vt.edu>
Last modified: Sat Oct 3013:15:51 1996