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CHAPTER 3 Relations
3.6 Summary
TERMS
congruent
quotient
divisible by
refines
equivalence class
remainder
equivalence relation
x =- y (mod p)
partition
THEOREMS
Let P be a partition of a set X. For x • y E X, define x - y to mean that x and y are in the
same element of the partition. Then, - is an equivalence relation. The equivalence classes
of - are exactly the elements of P.
3.8 Summary
TERMS
above
maximal
ASCII code
maximum
below
minimal
comparable
minimum
dictionary ordering
optimal
divides
partial ordering
embedding
strict partial ordering
law of trichotomy
total ordering
lexicographical ordering
linear ordering
ALGORITHMS
Finding a Minimal Element
3.10 Summary
TERMS
attribute
query
cartesian product
relational algebra
database
relational database
equijoin
selection
join
table
natural join
tuples
projection
value
quadruples
ALGORITHM
Join Two Relations