  Significant efforts have been expended in the research and development of a
database management system (DBMS) that has a wide range of applications for
managing an enormous collection of multisource, heterogeneous, complex, or
growing data. Besides the primary function (i.e., create, delete, and update),
a practical and impeccable DBMS can interact with users through information
selection, that is, querying with their targets. Previous querying algorithms,
such as frequent itemset querying and sequential pattern querying (SPQ) have
focused on the measurement of frequency, which does not involve the concept of
utility, which is helpful for users to discover more informative patterns. To
apply the querying technology for wider applications, we incorporate utility
into target-oriented SPQ and formulate the task of targeted utility-oriented
sequence querying. To address the proposed problem, we develop a novel
algorithm, namely targeted high-utility sequence querying (TUSQ), based on two
novel upper bounds suffix remain utility and terminated descendants utility as
well as a vertical Last Instance Table structure. For further efficiency, TUSQ
relies on a projection technology utilizing a compact data structure called the
targeted chain. An extensive experimental study conducted on several real and
synthetic datasets shows that the proposed algorithm outperformed the designed
baseline algorithm in terms of runtime, memory consumption, and candidate
filtering.
