60- , , .. . IBM - . (Codd E.F., A Relational Model of Data for Large Shared Data Banks. CACM 13: 6, June 1970), , , " ".
. (, , , ). , , relation (.) [3, 7, 9].
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D1, D2,..., Dn ( , ) . . 3.1 (. 1.1).
( . 1.1 ) A1, A2,..., An, Ai Di (i=1,2,...,n).
. 3.1. (Ai - , Vi - )
, - (Ai:Vi), (i=1,2,...,n), Ai . - (Ai:Vi) Vi Di, Ai.
. , , ,..., n n-. "" (. 1.1) 8.
. "" 10. .
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: R Ai, Aj,..., Ak.
: Ai, Aj,..., Ak K .
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, .