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Recent questions tagged relational-algebra

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GO Classes 2023 | IIITH Mock Test 3 | Question: 30
Consider the relations $r, s$ and query : $ \begin{gathered} t 1 \leftarrow \sigma_\theta((r \times s) \div r)\\ t 2 \leftarrow \sigma_\theta(s)\\ t 3 \leftarrow \sigma_\theta(r)\\ \end{gathered} $ Relation $r$ is not empty. Which of the following is correct? $t 1=t 3$ t2 $=t 3$ $t 1=t 2$ None of the above

GO Classes asked in Databases Apr 15

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GO Classes 2023 | IIITH Mock Test 3 | Question: 33
Consider the relations $R(A,B,C)$ and $S(B,C,D)$ and the following SQL queries. Select distinct $\ast$ from $R,S;$ Select distinct $\ast$ from $R,S$ where $R.C = S.C;$ Select distinct $\ast$ from $R,S$ where $R.C = S.C$ and $R.B = S.B;$ ... $i-d,ii-a,iii-c,iv-b$ $i-b,ii-a,iii-d,iv-c$ $i-d,ii-a,iii-b,iv-c$ $i-c,ii-a,iii-b,iv-d$

GO Classes asked in Databases Apr 15

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GO Classes 2023 | IIITH Mock Test 2 | Question: 84
Let $\mathrm{R}(a, b, c, d)$ be a RDBMS relation having the following set of functional dependencies(FD set) : FD Set $\mathrm{F}=\{b \rightarrow c ; c \rightarrow d ; ab \rightarrow d ; bc \rightarrow cd\}$ We apply some queries on a relational instance $r$ ... instance $r?$ $\prod_a(r)$ $\prod_{a, c}(r)$ $\prod_{a, b}(r)$ $\prod_{a, b, d}(r)$

GO Classes asked in Databases Apr 8

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Database: Relational Algebra
Let R be a relation of degree 5 then the total number of projections possible on R is ___?

Ashutosh_17 asked in Databases Mar 30

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GO Classes 2023 | IIITH Mock Test 1 | Question: 47
Consider the following relations and query. $ \begin{gathered} \textsf{r(A, B, C)}\\ \textsf{s(A, B, C)}\\ \sigma_{\textsf{A>C}}([(\textsf{r} \cup \text{s) - (r - s)] - (s - r))} \end{gathered} $ Which of the following is ... $\sigma_{\textsf{A>C}}(\text{r} \cap \textsf{s})$

GO Classes asked in Databases Mar 26

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GATE CSE 2023 | Memory Based Question: 34
Which one of the options given below refers to the degree (or arity) of a relation in relational database systems? Number of tuples stored in relation. Number of distinct domains of its relation schema. Number of attributes in relation. Number of entries in relation.

GO Classes asked in Databases Feb 6

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Dknights asked in Databases Dec 7, 2022

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a) Following relational schema is given: Doctor (DName, Reg_no,D_City), Patient (Pname, Disease, P_City) and Assigned To (Pname, Dname) Give expression in Relational Algebra for each of the queries: i) Get the names of patients who are assigned to more than one doctor. ii) Get the names of doctors who are treating patients with 'Polio’. iii) Get the details of doctors who are treating to the patient belongs to the same city. iv) Count the number of patients treated by each doctor

ayushrathore111 asked in Databases Nov 29, 2022

by ayushrathore111

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Recent questions tagged relational-algebra