We extend the relational model of data to consider classes as attribute values, thereby to allow eary and convernient the representation of quantified queries. Facts regarding object classes can be stored and manipulated in the same way as facts regarding object instances. Our model is upwards compatible with the standard relational model | ’ Tap ch´ Tin hoc v` Diˆu khiˆn hoc, , (2008), 42–49 ı a ` e e . . . ´ ´ ˆ ˆ INH DU. LIEU DOI CAC TRUY VAN DINH ˜ ˆ ˆ ´ ´ ˆ MOT MO H` . . . . ˜ ˆ NGUYEN KIM ANH Khoa Cˆng nghˆ thˆng tin - Dai hoc B´ch khoa H` nˆi o e o ` a a o . . . . Abstract. We extend the relational model of data to consider classes as attribute values, thereby to allow eary and convernient the representation of quantified queries. Facts regarding object classes can be stored and manipulated in the same way as facts regarding object instances. Our model is upwards compatible with the standard relational model. ´ ’ o e a o T´m t˘t. Ch´ ng tˆi mo. rˆng mˆ h` d˜. liˆu quan hˆ dˆ cho ph´p c´c l´.p nhu. c´c gi´ tri thuˆc o a u o o ınh u e e e a a . o . . . ’ . ’ ˜ a ˜ a ´ . ’.i vˆy, cho ph´p biˆu diˆn c´c truy vˆn dinh mˆt c´ch dˆ d`ng v` thuˆn tiˆn . t´ v` bo a ınh a e e e a o a e a a e . . . . . ’ ´ ´ o C´c su. kiˆn xem x´t c´c l´.p dˆi c´ thˆ tr˜. v` thao t´c giˆng nhu. c´c su. kiˆn xem a . e e a o o e u a a o a . e . . . . ’ . ’ ´ x´t c´c thˆ hiˆn dˆi . Mˆ h` cua ch´ ng tˆi l` th´ v´.i mˆ h` quan hˆ chuˆ n. e a e e o o ınh ’ u o a ıch o o ınh e a . . ˆ ´. 1. GIO I THIEU . ´ ’ Ph´p chia l` mˆt ph´p to´n cua dai sˆ quan hˆ hiˆn mˆt thao t´c kiˆ m tra ch´.a e a o e a e . e o a e’ u . . o . . . . dˆy, mˆt tˆp biˆ u diˆn mˆt nh´m c´c bˆ. Ph´p chia tˆ ng qu´t [5] mo. rˆng ’ ˜ ` ’ o tˆp nhiˆu-mˆt, o a a e o ’ o a e’ e o o a o e o a . . . . . . . .`.ng v´.i viˆc hiˆn c´c thao t´c kiˆ m tra ch´.a tˆp nhiˆu-nhiˆu. Ph´p to´n ` ` ph´p chia thu o e o e e a a e’ u a e e e a . . . . . tu. nhu. ph´p kˆt nˆi ch´.a tˆp dˆi v´.i c´c co. so. d˜. liˆu quan hˆ (CSDL) ´ ´ ´ ’ u e e e o u a e n`y c˜ng tu a u o o a . . . . ’ ’. dang chuˆ n 1. Hiˆn tai, khˆng mˆt ph´p chia n`o c`i d˘t tu.`.ng minh trong khˆng o . o a e . o o e a o . . . a a . ´ ` ´ e ’ c´c hˆ quan tri CSDL (DBMS), m˘c d` c´c ph´p to´n n`y giai quyˆt nhiˆu
