License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.ECOOP.2016.2
URN: urn:nbn:de:0030-drops-60968
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Avgustinov, Pavel ; de Moor, Oege ; Jones, Michael Peyton ; Schäfer, Max

QL: Object-oriented Queries on Relational Data

LIPIcs-ECOOP-2016-2.pdf (0.6 MB)


This paper describes QL, a language for querying complex, potentially recursive data structures. QL compiles to Datalog and runs on a standard relational database, yet it provides familiar-looking object-oriented features such as classes and methods, reinterpreted in logical terms: classes are logical properties describing sets of values, subclassing is implication, and virtual calls are dispatched dynamically by considering the most specific classes containing the receiver. Furthermore, types in QL are prescriptive and actively influence program evaluation rather than just describing it. In combination, these features enable the development of concise queries based on reusable libraries, which are written in a purely declarative style, yet can be efficiently executed even on very large data sets. In particular, we have used QL to implement static analyses for various programming languages, which scale to millions of lines of code.

BibTeX - Entry

  author =	{Pavel Avgustinov and Oege de Moor and Michael Peyton Jones and Max Sch{\"a}fer},
  title =	{{QL: Object-oriented Queries on Relational Data}},
  booktitle =	{30th European Conference on Object-Oriented Programming (ECOOP 2016)},
  pages =	{2:1--2:25},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-014-9},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{56},
  editor =	{Shriram Krishnamurthi and Benjamin S. Lerner},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-60968},
  doi =		{10.4230/LIPIcs.ECOOP.2016.2},
  annote =	{Keywords: Object orientation, Datalog, query languages, prescriptive typing}

Keywords: Object orientation, Datalog, query languages, prescriptive typing
Collection: 30th European Conference on Object-Oriented Programming (ECOOP 2016)
Issue Date: 2016
Date of publication: 18.07.2016

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