Browsing by Author "Gao, Qiao"

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    Temporal Keyword Search with Aggregates and Group-By
    (2021-07) Gao, Qiao; Lee, Mong Li; Ling, Tok Wang
    Abstract. Temporal keyword search enables non-expert users to query temporal relational databases with time conditions. However, aggregates and group-by are currently not supported in temporal keyword search, which hinders querying of statistical information in temporal databases. This work proposes a framework to support aggregate, group-by and time condition in temporal keyword search. We observe that simply combining non-temporal keyword search with aggregates, group-by, and temporal aggregate operators may lead to incorrect and meaningless results as a result of data duplication over time periods. As such, our framework utilizes Object-Relationship-Attribute semantics to identify a unique at-tribute set in the join sequence relation and remove data duplicates from this attribute set to ensure the correctness of aggregate and group-by computation. We also consider the time period in which temporal at-tributes occur when computing aggregate to return meaningful results. Experiment results demonstrate the importance of these steps to retrieve correct results for keyword queries over temporal databases.