The precise definition of Model D
logical and physical operators
is somewhat arbitrary.
Part of the reason for this is the
experimental nature of Model D.
When several
different approaches were available,
we wanted
to try each one
to see the
ramifications of the different strategies.
The rules set consists of
transformation,
implementation and
enforcement rules,
their antecedent
(before pattern)
and consequent,
their conditions for firing
and how the consequent expressions are constructed.
The catalog
describes what information
(
meta data)
describing
each stored relation and all defined indices
is required in order calculate
logical properties and evaluate rule conditions.
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