Graphical Query Languages for Semi-Structured Information.
Sara Comai · 2000
The amount of different kinds of data available electronically has increased rapidly in the last years. Beside strongly structured data obeying a rigid schema (e.g. data stored in databases), lots of data which do not present an a priori-known internal structure are spreading. Much of such data, though unstructured at a first sight, present a logical organization and can be considered semistructured [1]. The most known example of semistructured data is represented by the Web. For such data source, the need of retrieving information is becoming more and more relevant: to date, the only way to extract Web information is to use keyword-based search engines and to browse individual pages. However, the results supplied by common search engines (e.g. Altavista [9], Lycos [19], and so on) are often perceived by users as unsatisfactory: only HTML objects are indexed, the result of Web searching is often a flat list of URLs, without any structure, and, above all, several documents not related ...