248 views
0 votes
0 votes
Given R (ABCDE)

FDS ARE A-->BC,C-->DE, D-->E

R1(ABCD) R2(DE)

FIND WHETHER ITS DECOMPOSITION IS VALID OR NOT  and Fd preserving too

1 Answer

Best answer
0 votes
0 votes
1) R1(ABCD) AND R2(DE)

$(R1\cap R2)^{+}=R1 or R2$.THEN IT IS LOSSLESS JOIN DEPENDENCY.

HERE $(R1\cap R2)^{+}=DE$.// SO IT IS LOSSLESS JOIN DEPENDENCY.

2)DEPENDECY PRESERVING

R1(ABCD)---- A->BC,C->D

R2(DE)---- D->E.

G={A->BC,C->D,D->E}

by transtivity rule C->D AND D->E THEN C->E.

SO G={A->BC,C->DE,D->E}

SO IT IS DEPENDENCY PRESERVING
selected by

Related questions

0 votes
0 votes
1 answer
2
phaniphani asked Nov 16, 2023
176 views
is it allowed in a B+ tree, while deletion to leave behind a key in internal nodes while deleting it from the leaf ?