ylfink@water.UUCP (ylfink) (02/25/86)
DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF WATERLOO
SEMINAR ACTIVITIES
COMPUTER SCIENCE COLLOQUIUM
- Tuesday, March 4, 1986.
Mr. Yannis Ioannidis of the University of California,
Berkeley will speak on ``Processing Recursion in Deduc-
tive Databases''.
TIME: 3:30 PM
ROOM: MC 1052
ABSTRACT
Recursion appears to be one of the most important
features of a database system enhanced with deductive
power. In such an environment, it has traditionally
been studied under the formalism of 1-st order logic,
focusing on recursive Horn clauses. We reformulate the
recursion problem in operator form, embedding it in a
particular algebraic structure. This enables us to get
more information about the mechanics of recursion. In
particular, alternative processing techniques are
revealed, which, depending on the database state, have
the potential of being more efficient than the tradi-
tional ones. The importance of including these alter-
native algorithms in the strategy space of a recursion
optimizer is illustrated by some examples.