Given a set of functional dependencies, the Armstrong relation is a relation which satisfies all the functional dependencies in the closure and only those dependencies. Unfortunately, the minimum-size Armstrong relation for a given set of dependencies can have a size which is an exponential function of the number of attributes in the dependencies considered.
Read more about this topic: Armstrong's Axioms
Famous quotes containing the words armstrong and/or relation:
“There dwelt a man in faire Westmerland,
Jonnë Armestrong men did him call,
He had nither lands nor rents coming in,
Yet he kept eight score men in his hall.”
—Unknown. Johnie Armstrong (l. 1–4)
“The adolescent does not develop her identity and individuality by moving outside her family. She is not triggered by some magic unconscious dynamic whereby she rejects her family in favour of her peers or of a larger society.... She continues to develop in relation to her parents. Her mother continues to have more influence over her than either her father or her friends.”
—Terri Apter (20th century)