Stefan Karl’s research while affiliated with Karlsruhe Institute of Technology and other places

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Publications (2)


Efficient consistency control in deductive databases
  • Chapter

January 2006

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12 Reads

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5 Citations

Lecture Notes in Computer Science

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Stefan Karl

In this paper a theoretical framework for efficiently checking the consistency of deductive databases is provided and proven to be correct. Our method is based on focussing on the relevant parts of the database by reasoning forwards from the updates of a transaction, and using this knowledge about real or just possible implicit updates for simplifying the consistency constraints in question. Opposite to the algorithms by Kowalski/Sadri and Lloyd/Topor, we are neither committed to determine the exact set of implicit updates nor to determine a fairly large superset of it by only considering the head literals of deductive rule clauses. Rather, our algorithm unifies these two approaches by allowing to choose any of the above or even intermediate strategies for any step of reasoning forwards. This flexibility renders possible the integration of statistical data and knowledge about access paths into the checking process. Second, deductive rules are organized into a graph to avoid searching for applicable rules in the proof procedure. This graph resembles a connection graph, however, a new method of interpreting it avoids the introduction of new clauses and links.


Efficient Consistency Control in Deductive Databases

June 1997

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3 Reads

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1 Citation

In this paper a theoretical framework for efficiently checking the consistency of deductive databases is provided and proven to be correct. Our method is based on focussing on the relevant parts of the database by reasoning forwards from the updates of a transaction, and using this knowledge about real or just possible implicit updates for simplifying the consistency constraints in question. Opposite to the algorithms by Kowalski/Sadri and Lloyd/Topor, we are neither committed to determine the exact set of implicit updates nor to determine a fairly large superset of it by only considering the head literals of deductive rule clauses. Rather, our algorithm unifies these two approaches by allowing to choose any of the above or even intermediate strategies for any step of reasoning forwards. This flexibility renders possible the integration of statistical data and knowledge about access paths into the checking process. Second, deductive rules are organized into a graph to avoid searching f...

Citations (1)


... The derivation of safe insertions and potential deletions is proposed, e.g., in [23, 37] . Calculating induced updates in different granularities has already been proposed by Moerkotte and Karl in [28], restricted to positive databases, though. The propagation rules proposed in this paper are restricted to the propagation of insertions and deletions of base facts in stratifiable databases. ...

Reference:

Optimizing continuous queries using update propagation with varying granularities
Efficient consistency control in deductive databases
  • Citing Chapter
  • January 2006

Lecture Notes in Computer Science