Querying Semistructured Heterogeneous Information

Abstract. Semistructured data has no absolute schema xed in advance and its structure may be irregular or incomplete. Such data commonly arises in sources that do not impose a rigid structure such as the World-Wide Web and when data is combined from several heterogeneous sources. Data models and query languages designed for well structured data are inappropriate in such environments. Starting with a lightweight" object model adopted for the TSIMMIS project at Stanford, in this paper we describe a query language and object repository designed speci cally for semistructured data. Our language provides meaningful query results in cases where conventional models and languages do not: when some data is absent, when data does not have regular structure, when similar concepts are represented using di erent types, when heterogeneous sets are present, and when object structure is not fully known. This paper motivates the key concepts behind our approach, describes the language through a ...

• Type: Conference
• Year: 1995
• Where: DOOD
• Authors: Dallan Quass, Anand Rajaraman, Yehoshua Sagiv, Jeffrey D. Ullman, Jennifer Widom
• Keywords: Database, DOOD 1995, Object Repository, Query Language, Such Data