tailieunhanh - Phân mảng trên giá trị lặp của các thuộc tính cơ sở dữ liệu quan hệ

The original database may be rebuilt from the subfragmentations and the aliases. The fragmentation of the given relational database by group of the repeated values of the attributes will save the needed memory, increase the processing speed of data. This work has been applied in people’s committee of Hatay province and its districts and precints. | ’ Tap ch´ Tin hoc v` Diˆu khiˆ n hoc, , (2007), 86—98 ı e e . . a ` . ’ ’ ˆ ˆ ´ ´ ˆ PHAN MANH TREN GIA TRI LAP CUA CAC THUOC T´ INH . ˘ . . . ’ . ˜. ˆ ˆ TRONG CO SO DU LIEU QUAN HE . . ˆ ˆ LE HUY THAP . Viˆn Cˆng nghˆ thˆng tin, Viˆn Khoa hoc v` Cˆng nghˆ Viˆt Nam e o e o e e e . . . . a o . . Abstract. This paper presents a method of fragmentation of the given relational database, in which there’s a number of attributes having the repeated values. The fragmentation is based on the principle of the horizontal, vertical and mixed fragmentations. The received fragmentations include the attributes having the repeated values and have the maximum size, then they are replaced by some aliases. The original database may be rebuilt from the subfragmentations and the aliases. The fragmentation of the given relational database by group of the repeated values of the attributes will save the needed memory, increase the processing speed of data. This work has been applied in people’s committee of Hatay province and its districts and precints. ´ ’ ’ u e T´m t˘t. B`i b´o gi´.i thiˆu ph´p phˆn manh co. so. d˜. liˆu quan hˆ d˜ cho v`o su. l˘p o a a a o e a a e a a . a . . . . . ´ ´ ’ ’ e e a a lai c´c gi´ tri cua mˆt sˆ thuˆc t´ a a . ’ o o o ınh. Viˆc phˆn manh trˆn nguyˆn t˘ c phˆn manh ngang, doc e a . . . . . . ˜ ´ ’ v` hˆ n . C´c manh thu ch´.a c´c thuˆc t´ c´ gi´ tri l˘p v` c´ k´ thu.´.c l´.n nhˆ t, sau a o a u a o ınh o a . a a o ıch o o a . . . . ´ ´ ’ ’ a ı ’ u e o ’ d´, c´c manh n`y thay c´c b´ danh. Co. so. d˜. liˆu gˆc t´i thiˆt lai t`. c´c manh con o a a e . u a . . . a . c´c b´ danh. Viˆc phˆn manh co. so. d˜. liˆu quan hˆ b˘ ng c´ch gom nh´m c´c gi´ tri l˘p cua ` ’ ’ u e ’ e a e a a o a a . a v` t` a ı a u . . . . . dung thˆng tin cˆn lai trong bˆ nh´. dˆ ng th`.i l`m t˘ng ` ´ e ` o a c´c thuˆc t´ s˜ tiˆt kiˆm du . a o ınh e e o a o o o a . . . . . ´ . tˆc dˆ xu. l´ d˜. liˆu. o o ’ y u e . ’.