Learn More
language, designed for querying semistructured data. Semistructured data is becoming more and more prevalent, e.g., in structured documents such as HTML and when performing simple integration of data from multiple sources. Traditional data models and query languages are inappropriate, since semistructured data often is irregular: some data is missing,(More)
Lore (for Lightweight Object Repository) is a DBMS designed specifically for managing semistructured information. Implementing Lore has required rethinking all aspects of a DBMS, including storage management, indexing, query processing and optimization, and user interfaces. This paper provides an overview of these aspects of the Lore system, as well as(More)
Research on semistructured data over the last several years has focused on data models, query languages, and systems where the database is modeled as some form of labeled, directed graph [Abi97, Bun97]. The recent emergence of eXtensible Markup Language (XML) as a new standard for data representation and exchange on the World-Wide Web has drawn significant(More)
XML is an emerging standard for data representation and exchange on the World-Wide Web. Due to the nature of information on the Web and the inherent exibility of XML, we expect that much of the data encoded in XML will be semistructured: the data may be irregular or incomplete, and its structure may change rapidly or unpredictably. This paper describes the(More)
Semistructured data is not strictly typed like relational or object-oriented data and may be irregular or incomplete. It often arises in practice, e.g., when heterogeneous data sources are integrated or data is taken from the World Wide Web. Views over semistructured data can be used to lter the data and to restructure (or provide structure to) it. To(More)
This paper describes techniques for building and exploiting indexes on semistructured data: data that may not have a xed schema and that may be irregular or incomplete. We rst present a general framework for indexing values in the presence of automatic type coercion. Then based on Lore, a DBMS for semistructured data, we introduce four types of indexes and(More)
The number of information sources accessible electronically is growing rapidly. Many of these sources store and export unstructured data in addition to or instead of structured data. In most cases, however, the unstructured data is not entirely devoid of structure, i.e., the data is semzstructured. We consider data to be semistructured when there is no(More)