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Issue No. 04 - December (1990 vol. 2)
ISSN: 1041-4347
pp: 401-409
<p>Data streams are long, relatively unstructured sequences of characters that contain information such as electronic mail or a tape backup of various documents and reports created in an office. A conceptual framework is presented, using relational algebra and relational databases, within which data streams may be queried. As information is extracted from the data streams, it is put into a relational database that may be queried in the usual manner. The database schema evolves as the user's knowledge of the content of the data stream changes. Operators are defined in terms of relational algebra that can be used to extract data from a specially defined relation that contains all or part of the data stream. This approach to querying data streams permits the integration of unstructured data with structured data. The operators defined extend the functionality of relational algebra in much the same way that the join does relative to the basic operators select, project, union, difference, and Cartesian product.</p>
data stream querying; unstructured sequences; electronic mail; tape backup; office; conceptual framework; relational algebra; relational databases; database schema; unstructured data; structured data; database theory; information retrieval systems; relational databases

C. Hartzman and C. Watters, "A Relational Approach to Querying Data Streams," in IEEE Transactions on Knowledge & Data Engineering, vol. 2, no. , pp. 401-409, 1990.
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