Base and Derived Relations
In a relational database, all data are stored and accessed via relations. Relations that store data are called "base relations", and in implementations are called "tables". Other relations do not store data, but are computed by applying relational operations to other relations. These relations are sometimes called "derived relations". In implementations these are called "views" or "queries". Derived relations are convenient in that they act as a single relation, even though they may grab information from several relations. Also, derived relations can be used as an abstraction layer.
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Famous quotes containing the words base and, base, derived and/or relations:
“Things base and vile, holding no quantity,
Love can transpose to form and dignity.
Love looks not with the eyes, but with the mind,
And therefore is winged Cupid painted blind.”
—William Shakespeare (1564–1616)
“It is a base thing for a man among the people not to obey those in command. Never in a state can the laws be well administered when fear does not stand firm.”
—Sophocles (497–406/5 B.C.)
“Ex oriente lux may still be the motto of scholars, for the Western world has not yet derived from the East all the light which it is destined to receive thence.”
—Henry David Thoreau (1817–1862)
“So soon did we, wayfarers, begin to learn that man’s life is rounded with the same few facts, the same simple relations everywhere, and it is vain to travel to find it new.”
—Henry David Thoreau (1817–1862)