Deductive Databases & Logic Programs: Back to the Future! Colloquium talk on the occasion of the retirement of Prof. Dr. Georg Lausen, May 10th, 2019, Universität Freiburg, Germany

1. Deduktive Datenbanken & Logische
Programme: Eine kleine Zeitreise
Deductive Databases & Logic Programs:
Back to the Future!
Bertram Ludäscher
ludaesch@illinois.edu
Wissenschaftl.
Kolloquium
Prof. Dr. Georg Lausen
Freitag, 10. Mai 2019
School of Information Sciences (iSchool@Illinois)
& National Center for Supercomputing Applications (NCSA)
& Department of Computer Science (CS@Illinois)
1

2. Outline
• “Wat isn’ en Datenbank?”
– … Da stelle mer uns janz dumm …
• Deductive Object-Oriented Databases: F-logic
– … caught in a strange loop?
• Statelog
– … understanding Datalog updates through states
• Answer Set Programming
– … from querying databases to CSP
• a secret sauce!
– Datalog + ASP for the rest of us
• … Possible Worlds Explorer!
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3. The Time-Travel begins …
Identify this Database Model!
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Hierarchical Model
(IBM 1960s)

4. … and what about this DB model?
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Network Model
(CODASYL standard 1970s)

5. … and another one!
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Relational Model
(E.F. Codd 1970)

6. … last not least: what’s this?
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[Nav92] Navathe, Shamkant B.: Evolution of Data Modeling for Databases. In: CACM, 35 (9). 1992.
Entity-Relationship Model
(P. Chen 1976)

7. Database Models & Paradigms
• ANSI-SPARC 3-level architecture
– External (user views)
– Conceptual (logical schema)
– Internal (physical schema)
• DB models:
– Hierarchical (~1960s)
– Network (~1970s)
– Relational (~1970s ..)
– Deductive (~1980s_90s ..)
• Negation & Nonmonotonic Reasoning
– Object-Oriented (~1990s)
– Object-Relational & DOOD
– Semistructured/XML (~2000s)
– Graph databases ...
– NoSQL …
– “Semantic Web”, Linked Open Data
– Knowledge Graphs …
– …
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[Nav92] Navathe, Shamkant B.: Evolution of Data
Modeling for Databases. CACM, 35 (9). 1992.

8. History and Provenance:
Understanding what happened!
… frozen accidents
Zrzavý, Jan, David Storch, and Stanislav
Mihulka. Evolution: Ein Lese-Lehrbuch.
Springer-Verlag, 2009.
Author: Jkwchui (Based on
drawing by Truth-seeker2004)
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9. The Evolution of Language
– Peter Buneman for Phil Wadler
9
The Evolution of Language
2x (Descartes)
x. 2x (Church)
(LAMBDA (X) (* 2 X)) (McCarthy)
<?xml version="1.0"?>
<LAMBDA-TERM>
<VAR-LIST>
<VAR>X</VAR>
</VAR-LIST>
<EXPR>
<APPLICATION>
<EXPR><CONST>*</CONST></EXPR>
<ARGUMENT-LIST>
<EXPR><CONST>2</CONST></EXPR>
<EXPR><VAR>X</VAR></EXPR>
</ARGUMENT-LIST>
</APPLICATION>
</EXPR>
</LAMBDA-TERM>
(W3C)
My own thesis:
• There’s no problem that can’t be
tackled by another level of
indirection.
.. and antithesis:
• Adding levels of indirection gets you
further away from solving your
problem.
.. and then:
Beware of the Turing tar-pit in which
everything is possible but nothing of
interest is easy.
-- Alan Perlis in Epigrams on Programming

10. Beware of Techno(re)ligion:
Great ideas are simple; frozen accidents aren’t …
• Heliocentric model
• Natural Selection
• Structure of DNA
• Genetic Code
• Relativity
• …
• Logic
F = A | F/F | -F | (ex x) F
10
vs
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11. Meanwhile in a galaxy far far away…
Semantic Web Stuff
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W3C Activities in Developing New Query Languages
[Man15] R. MANTHEY . Back to the Future – Should SQL Surrender to SPARQL? SOFSEM, LNCS, 2015.

12. Are we caught in a strange loop?
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[Man15] R. MANTHEY . Back to the Future – Should SQL Surrender to SPARQL? SOFSEM, LNCS, 2015.

13. Computational Thinking: Die Grenzen meiner
Sprache bedeuten die Grenzen meiner Welt …
• Vanilla Process Network
• Functional Programming
Dataflow Network
• XML Transformation
Network
• Collection-oriented
Modeling & Design
framework (COMAD)
– Look Ma: No Shims!
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14. One Rule to Rule them All!
• win(X) :- move(X,Y), not win(Y).
- “Not stratified! Go away!”
- .. the well-founded model yields what we want!
- … all Fixpoint Queries expressible by 1 rule!
- (and a simply definable move/2 relation)
- … solved games represent their own provenance
(data lineage, justification)
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• def(X) :- attacks(Y,X), not def(Y).
– ... and apply stable models (answer set) semantics
– … we obtain Argumentation Frameworks

15. Deductive Rules + Object-Orientation
=> Frame-Logic
• Synthesis of deductive DBs + OO-DBs was “in the air”
– [Mai86] D. Maier. A Logic for Objects. Workshop on Foundations
of Deductive Databases and Logic Programming, 1986.
– F-Logic hit all the right points!
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1999 ACM SIGMOD
Test of Time Award!

16. Ludäscher: Kleine Zeitreise 16
The “Bible” for a Generation
of PhD Students
[KLW95] KIFER, MICHAEL ; LAUSEN, GEORG ; WU, JAMES: Logical Foundations of
Object-oriented and Frame-based Languages. J. ACM. 42 (4), 741–843, 1995

17. From F-logic to FLORID (… to Statelog)
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• “My Generation”: U Mannheim, U Freiburg overlap ..
– B. Marx, H. Uphoff, J. Frohn, P.T. Kandzia, B.
Ludäscher, W. May, R. Himmeröder, C.
Schlepphorst
• F-logic implementations
– FLORID
• C++ based
• interpreted
– “FLIP”
• XSB-Prolog based
• … Flora …
• … Flora2

18. Ludäscher: Kleine Zeitreise 18
From a reviewer:
“This paper comes
too late…”

19. F-logic database schema and instance
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20. F-logic database schema and instance
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21. F-logic queries
and
path expressions
over DOODs
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22. Semi-Structured Databases in F-logic
• semistructured ?
• semi-structured ?
• semi-structured ?
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23. DBLP site as a semi-structured DB
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24. Path Expressions over Graphs
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25. How to derive new relations
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26. … with just a few rules!
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27. Application: Web Crawling & Querying
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28. Extracting Data and Querying the Web
(F-logic’s DOOD + text extraction)
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29. Querying a Web Skeleton with Florid
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F-logic
query ..
answer
Mosaic …
… no
more
Easter
Egg

30. Pop Quiz 2: Reference Bingo!
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31. Updates a New Frontier!
• Started at U Mannheim (KA => MA commute)
– Updates = Datalog + States ?
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32. A language for declaring updates & change:
Statelog: Datalog + States
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33. Ludäscher: Kleine Zeitreise 33
OLD is NEW again!
- PODS’10 Keynote by Joe Hellerstein
- LogicBlox, Lixto? …

34. Updates a New Frontier!
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35. ASP: Answer Set Programming + PWE
A SuperPower for “Doing Semantics”
Bertram Ludäscher
Sahil Gupta
Jessica Cheng
School of Information Sciences
Department of Computer Science

36. Datalog .. ASP: Hitting KR&R Sweet Spots
36
Variations
on FOL +
Recursion +
Negation
=
S/I/W/P/… -
Datalog
… ASP ...
Many Results from Theory
Getting Things Done with Jupyter notebooks & Python
RPQ:
similar
Unique 3-valued Model
vs
Set of Stable Models

37. • Euler/X project employs
qualitative reasoning (RCC-5),
implemented in ASP to align,
merge taxonomies, debug
alignments, etc.
37
Reasoning with Incomplete Knowledge:
Exploring Possible Worlds

38. 38
Y X X YX Y X Y X Y
Congruence
X == Y
Inclusion
X > Y
Inverse Inclusion
X < Y
Overlap
X>< Y
Disjointness
X ! Y
Origins:
Euler diagrams ...
... limited FO reasoning
... RCC-5++ reasoning
Application: Geo-Taxonomy Alignment
The secret sauce inside: Moved from FO reasoner to … qualitative reasoning
(RCC-5) to … Answer Set Programming (ASP) + some more secret sauce
Taxonomy Alignment Problem

39. So there is only 1 possible world?
• If you believe what you hear,
there only seems to be one
possible government coalition
after the 2017 German
parliamentary elections:
• Jamaica!
– CDU + FDP + Grüne
39Ludäscher: Provenance Back & Forth

40. Not so fast: There are 31 possible worlds!
40
Only 5 logic
rules needed to
encode all the
semantics!
1-liner to count
possible worlds: 31
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41. … still 16 worlds when excluding “GroKo” coalitions
(= Great Coalition of CDU & SPD)
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42. ASP + PWE: Possible Worlds Explorer
42
https://github.com/idaks/PW-explorer https://github.com/idaks/PWE-demos

43. 43

44. Let’s Go Forward with
Deductive Rules!
or
Back to the Future!
(The End)
Demos & More: LATER!
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All those moments
will be lost in time,
like tears in rain

45. Want to know more?
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46. Reference Quiz: Solution
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47. Reference Quiz: Solution
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48. Reference Quiz Solution
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