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Recent questions tagged relational-algebra

3 votes
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245
Online test
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4 votes
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246
Online test
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4 votes
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1 votes
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249
Explain Division Operator
R/S is defined as ${\prod }_{R-S} (r) - {\prod }_{R-S} \begin{pmatrix} \left \langle {\prod }_{R-S} (r) \times S \right \rangle - {\prod }_{R-S,S} (r) \end{pmatrix}$ Please explain the validity of the statements with example
R/S is defined as${\prod }_{R-S} (r) - {\prod }_{R-S} \begin{pmatrix} \left \langle {\prod }_{R-S} (r) \times S \right \rangle - {\prod }_{R-S,S} (r) \end{pmatrix}$Please...
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5 votes
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253
ISRO2008-33
The join operation can be defined as a cartesian product of two relations followed by a selection a cartesian product of two relations a union of two relations followed by cartesian product of the two relations a union of two relations
The join operation can be defined asa cartesian product of two relations followed by a selectiona cartesian product of two relationsa union of two relations followed by c...
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8 votes
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254
ISRO2007-52
Which operation is used to extract specified columns from a table? Project Join Extract Substitute
Which operation is used to extract specified columns from a table?ProjectJoinExtractSubstitute
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2 votes
2 answers
255
ISI2011-PCB-CS-5a
Consider relations $R(A, B)$ and $S(B, C)$. Find a propositional formula $\phi$ such that the following two relational algebra expressions produce the same answer. $\pi_{A,B}(\sigma_\phi(R \bowtie S))$ $R \cap ({\rho_T(A)}(\pi_C(S)) \times \pi_B(S))$
Consider relations $R(A, B)$ and $S(B, C)$. Find a propositional formula $\phi$ such that the following two relational algebra expressions produce the same answer.$\pi_{A...
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1 votes
1 answer
258
DB \ relational algebra
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2 votes
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260
tuples
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2 votes
1 answer
261
validity of relational algebra query
Let R and S be two relations, and l be an attribute common to R and S. Let c be a condition over the attributes common to R and S. Prove or disprove the following:
Let R and S be two relations, and l be an attribute common to R and S.Let c be a condition over the attributes common to R and S. Prove ordisprove the following:
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26 votes
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262
GATE CSE 1992 | Question: 13b
Suppose we have a database consisting of the following three relations: ... are liked by each customer. Express the following query in relational algebra: Print the hotels the serve the snack that customer Rama likes.
Suppose we have a database consisting of the following three relations:$$\begin{array}{|c|c|} \hline \text {FREQUENTS} & \text {(CUSTOMER, HOTEL)} \\\hline \text {SERVES}...
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3 votes
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265
maximum no of tuples
Consider the relation R1( P, Q, R, S ) and R2 ( R, G, T, U ) The relation R1 has 20 tuples and R2 has 10 tuples then maximum number of tuples in R1 ⟕ R2 is .......................?
Consider the relation R1( P, Q, R, S ) and R2 ( R, G, T, U )The relation R1 has 20 tuples and R2 has 10 tuples then maximum number of tuples in R1 ⟕ R2 is ...........
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1 votes
1 answer
269
Relational Algebra
Whats wrong with option A.
Whats wrong with option A.
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