WWW: Beyond the Basics

15. Searching and Databases on the Web

15.1. Introduction

The World Wide Web, or the Web, has grown fast in recent years. It has become a very popular and interesting place that many people would like to spend time on. It is fun to browse through documents, to learn skills by reading books on the Web, to read news, and to do business and commerce on the World Wide Web, and so on. Sometimes what we really want is to be able to find things like we can in the library. In recent years, many search systems and search tools become available on the Web. But how do they work? how can we select an ideal search service that best satisfies our needs? These questions caught our attention. For this reason, we investigate search systems for the World Wide Web.

Suppose that we were to built a search system for the World Wide Web as the conventional library's search system. Think about what we need to do. First, we need to create catalogies or indexes of the documents (``books'') as the conventional library and traditional database do. More exactly, we need to collect information about resources or documents over the World Wide Web, determine terms to be indexed; then create a record for each document, and put into database. The former process is called gathering process, and the latter is called indexing process. A database is a set of records. Each record is a brief description of a resource or document. Essentially every search service is database search. The searching process is searching the database built during the indexing process. To search, or to query database, certain query language and search engine have to be used. The query language takes a question from the user, transfers that question into a formal query that search engine can understand. The search engine takes that query, then applies the query to the index (database) and finds a set of records (called the result set) that satisfies the criteria specified in the user's question. The result set contains information that meets the user's needs, description of resources, such as a list of links to articles on the topic of interest. Finally the search system should have capability of providing the original resources to the user. In this process (called the retrieval process), the system transfers the original document to a local system, where it can be viewed, saved, or printed. If the user is given a list of links, URLs (Uniform Resource Locations), this could be done easily in the way that the Web browser and the Web server do. Briefly a search system for the World Wide Web would likely consists of the following four functional modules as described in Yeager et. al.'s Book [Yeager96]:

This chapter helps us to find an easy way to understand the principle of search systems for the World Wide Web, and discusses indexing and searching technologies for Database.

Next we will examine how each module of search system works and processes in more detail.

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Copyright © 1996 Aixiang (I Song) Yao, All Rights Reserved

Aixiang (I Song) Yao<ayao@csgrad.cs.vt.edu>
Last modified: November 20, 1996