R(a,b) currently contains the four tuples (0,4), (1,5), (2,4), and (3,5). S(c,d)
ID: 3545186 • Letter: R
Question
R(a,b) currently contains the four tuples (0,4), (1,5), (2,4), and (3,5). S(c,d) currently contains the four tuples (2,10), (3,11), (4,12), and (5,13). As a result, certain insertions and deletions on R and S are illegal. You should develop simple tests for illegal operations of these four kinds. Then, show your understanding by indicating which of the following modifications will notviolate any constraint.
R(a,b) currently contains the four tuples (0,4), (1,5), (2,4), and (3,5). S(c,d) currently contains the four tuples (2,10), (3,11), (4,12), and (5,13). As a result, certain insertions and deletions on R and S are illegal. You should develop simple tests for illegal operations of these four kinds. Then, show your understanding by indicating which of the following modifications will notviolate any constraint.
Here are declarations of tow relations R and S:Explanation / Answer
R S
a b c d
0 4 2 10
1 5 3 11
2 4 4 12
3 5 5 13
Deleting (0,4) from R. will not violet any condition.
Inserting (3,4) into R will voilet the primary key constraints.
Deleting (4,12) from S. will voilet the foreign key constraint since 4 is reference by cloumn b in R.
Inserting (4,10) into S will voilet the primary key constraints.
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