Preference Queries with SV-Semantics.

摘要: Personalization of database queries requires a semantically rich, easy to handle and flexible preference model. Building on preferences as strict partial orders we provide variety intuitive base constructors for numerical categorical data, including so-called d-parameters. As novel semantic concept complex introduce the notion ‘substitutable values’ (SV-semantics), characterizing equally good values amongst indifferent values. Pareto prioritized construction preserves orders, which instantly solves crucial wellknown problems queries. We can point out new semantic-guided way cope with infamous flooding effect query engines. Contrary wide-spread belief give evidence that result sizes or skyline not necessarily explode multiple attributes. Moreover, show known laws from relational algebra remain valid under SV-semantics. Since most these rely transitivity, preservation order is essential algebraically optimize Similarly, well-known efficient evaluation algorithms selection operator transitivity. In nutshell, SVsemantics enable an powerful personalization at same time are key evaluation.