Date of Award:
Master of Science (MS)
In a relational temporal database, typically each row of each table has a period timestamp to indicate the lifetime of that row. In order to evaluate a query in a temporal database, sequenced semantics comes into play. The semantics stipulates that the query must be evaluated simultaneously in each time instant using the data rows available at that point of time. Existing researches have proposed changes in the query evaluation engine to achieve sequenced semantics. In this paper we show a way to support sequenced semantics without modifying the query engine. We propose a noble construction log-segmented label to represent the lifetime and replace the period timestamp from each row with a log-segmented label that signifies when the tuple is alive. Then we translate a sequenced query to a non-temporal query by utilizing the properties of log-segmented label. The translated query has only operations already available in a typical relational database making the query readily executable in an unaltered installation of the database. Thus the sequenced query inevitably runs and retrieve data without changing query evaluation engine. Finally our implementation using Java language, ANTLR parser generator and PostgreSQL database demonstrates the feasibility of the proposed mechanism, which, to the best of our knowledge, has not been previously shown.
Ahsan, M. A. Manazir, "Achieving a Sequenced, Relational Query Language with Log-Segmented Timestamps" (2021). All Graduate Theses and Dissertations. 8227.
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