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|Authors:||Sarah Mallet and Mireille Ducassé|
|Article title:||DDB Trees: A Basis for Deductive Database Explanations|
|Conference:||AADEBUG'97. Proceedings of the Third International Workshop on Automatic Debugging: Linköping, Sweden, May 26-27, 1997|
|Abstract [en]:||The power of deductive systems in general is that
programs express what should be done and not how it should be done.
Nevertheless, deductive systems need debugging and explanation
facilities. Indeed, their operational semantics is less abstract than
the declarative semantics of the programs. If users have to understand
all the low level details of the operational semantics much of the
benefits of using a deductive system is lost.
Existing explanation systems for deductive databases produce proof trees to be shown to users. Although useful, proof trees give a fragmented view of query evaluations, and users face a, most of the time large, forest of proof trees.
We propose a new data structure, called the DDB tree, which merges the information of a proof tree forest into one concise tree. A DDB tree gives a global picture of a query evaluation in a dramatically reduced structure with no loss of information. DDB trees can be shown to users or can be analyzed further by an explanation system.
|Keywords:||Debugging, explanations, deductive databases, logic programming|
|Publisher:||Linköping University Electronic Press|
|No. of pages:||16|
|Series:||Linköping Electronic Articles in Computer and Information Science|
|Series:||Linköping Electronic Conference Proceedings|
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