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5 votes
4 answers
2671
Why is the maximum number of tuples in full outer join equal to m*n ?
Why is the maximum number of tuples in full outer join equal to m*n, where m is the number of attributes in one relation and n is the attribute count in other ? Can someone give an example to illustrate this ?
Why is the maximum number of tuples in full outer join equal to m*n, where m is the number of attributes in one relation and n is the attribute count in other ?Can someon...
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5 votes
2 answers
2673
Is the following type of dependencies allowed in 3NF- ?
Is the following type of dependencies allowed in 3NF- ? A-->B where A is a proper subset of CK and    B is proper subset of another CK.
Is the following type of dependencies allowed in 3NF- ?A >Bwhere A is a proper subset of CKand    B is proper subset of another CK.
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6 votes
4 answers
2674
3NF is inadequate in situations where the relation:
3NF is inadequate in situations where the relation: A. has multiple candidates key B. has candidate key that are composite C. has overlapped candidate keys D. all the above
3NF is inadequate in situations where the relation:A. has multiple candidates keyB. has candidate key that are compositeC. has overlapped candidate keysD. all the above
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0 votes
0 answers
2678
why are both SIX and SIX not compatible to each other ?
If a node is already in SIX mode then why can't another transaction lock it again in SIX mode ?since this implies that some another transaction is trying to apply exclusive lock on some node below this current node , so then what 's the issue ?
If a node is already in SIX mode then why can't another transaction lock it again in SIX mode ?since this implies that some another transaction is trying to apply exclusi...
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0 votes
2 answers
2680
how to approach this type of question
i know how to find whether the decomposition is lossless or lossy . but in this type of question they are actually not defining how they decompose . they are only giving a set of functional depenencies . how to solve this type of question
i know how to find whether the decomposition is lossless or lossy . but in this type of question they are actually not defining how they decompose . they are only giving ...
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0 votes
1 answer
2684
Consider the relation R(A,B,C,D) with dependencies AB -> C, ABC -> D and AC ->>- B.
R is not in 3NF R is in 3NF but not in BCNF R is in BCNF but not in 4NF R is in 4NF How to approach this ques ?
R is not in 3NF R is in 3NF but not in BCNF R is in BCNF but not in 4NF R is in 4NF How to approach this ques ?
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1 votes
1 answer
2685
Canonical cover is in which normal form ?
I am just having one confusion that if we have a canonical cover so it doesn't have any extraneous attributes or redundancy , so is it always in normal form, or not always true ,i.e it may depend on whether it satisfies all the conditions for being in normal form .
I am just having one confusion that if we have a canonical cover so it doesn't have any extraneous attributes or redundancy , so is it always in normal form, or not alway...
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0 votes
1 answer
2686
Consider a relational table r with sufficient number of records, having attributes A1, A2,…, An and let 1 <= p <= n.
The database can be configured to do ordered indexing on Ap or hashing on Ap. Which of the following statements is TRUE?(A) Ordered indexing will always outperform hashin...
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1 votes
1 answer
2689
why is the below statement regrading weak entity correct ?
Weak entity set avoids the data duplication and consequent possible inconsistencies caused by duplicating the key of the strong entity.. plz clarify this........
Weak entity set avoids the data duplication and consequent possible inconsistencies caused by duplicating the key of the strong entity..plz clarify this........
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0 votes
1 answer
2691
If there are mapping constraints in the E-R diagram , can we reduce the size of the table ?
I am not getting that how many attributes must be there in the Borrowed by table which actually represents a table since we have the constraint that one user can borrow only one book .
I am not getting that how many attributes must be there in the Borrowed by table which actually represents a table since we have the constraint that one user can borrow o...
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1 votes
2 answers
2693
database
decompose relation into 2NF ,3NF,BCNF R(ABCDE) {AB--->C, DE----->C , B------->D} R(ABCD) {AB----->C,C-------->D,D-------->A}
decompose relation into 2NF ,3NF,BCNFR(ABCDE) {AB ->C, DE ->C , B ->D}R(ABCD) {AB ->C,C >D,D >A}
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1 votes
1 answer
2694
A relation R(ABCDE) with FD set f = {A -> BC, C -> DE, D -> E} and the decomposition d = { R1(ABCD), R2(DE)}. Is this decomposition dependency preserving?
The answer given is YES. But how is the dependency C - DE preserved in this decomposition?
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14 votes
4 answers
2696
solve
How many view equal serial schedules possible for the following schedule? S : w1(A) r2(A) w3(A) r4(A) w5(A) r6(A) w7(A) r8(A
How many view equal serial schedules possible for the followingschedule?S : w1(A) r2(A) w3(A) r4(A) w5(A) r6(A) w7(A) r8(A
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0 votes
1 answer
2697
explain!
Suppose a phone book contain 500 pages and each page can contain upto 500 records. Suppose we want to search for a particular name in a phone book. Give a worst case bound on number of pages that must be looked to perform a search using an index for the name of the first entry of each page??
Suppose a phone book contain 500 pages and each page can containupto 500 records. Suppose we want to search for a particular name in aphone book. Give a worst case bound ...
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1 votes
1 answer
2698
database explain
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0 votes
2 answers
2699
explain
If R and S are two relation in BCNF the natural join of R and S is also in BCNF. above statement true or false.??
If R and S are two relation in BCNF the natural join of R and S is alsoin BCNF.above statement true or false.??
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0 votes
1 answer
2700
give statement in english for SQL
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