61. | R(A,B,C,D) is a relation. Which of the following does not have a lossless join, dependency preserving BCNF decomposition? |
Discuss |
Answer: (c).AB->C, C->AD
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62. | Consider a relation geq which represents “greater than or equal to”, that is, (x,y) ∈ geq only if y >= x. create table geq ( ib integer not null ub integer not null primary key 1b foreign key (ub) references geq on delete cascade ) Which of the following is possible if a tuple (x,y) is deleted? |
Discuss |
Answer: (c).A tuple (z,w) with w < x is deleted
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63. | Given the following relation instance. x y z 1 4 2 1 5 3 1 6 3 3 2 2 Which of the following functional dependencies are satisfied by the instance? (GATE CS 2000) |
Discuss |
Answer: (b).YZ -> X and Y -> Z
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64. | Consider the relation X(P, Q, R, S, T, U) with the following set of functional dependencies F = { {P, R} → {S,T}, {P, S, U} → {Q, R} } Which of the following is the trivial functional dependency in F+ is closure of F? |
Discuss |
Answer: (c).{P,S}→{S}
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65. | A relational database contains two tables student and department in which student table has columns roll_no, name and dept_id and department table has columns dept_id and dept_name. The following insert statements were executed successfully to populate the empty tables: Insert into department values (1, 'Mathematics') Insert into department values (2, 'Physics') Insert into student values (l, 'Navin', 1) Insert into student values (2, 'Mukesh', 2) Insert into student values (3, 'Gita', 1) How many rows and columns will be retrieved by the following SQL statement? Select * from student, department |
Discuss |
Answer: (d).6 rows and 5 columns
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66. | A table has fields Fl, F2, F3, F4, F5 with the following functional dependencies F1 → F3 F2→ F4 (F1 . F2) → F5 In terms of Normalization, this table is in |
Discuss |
Answer: (a).1 NF
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67. | Which of the following is NOT a superkey in a relational schema with attributes V, W, X, Y, Z and primary key V Y ? |
Discuss |
Answer: (b).V W X Z
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68. | Let R (A, B, C, D, E, P, G) be a relational schema in which the following functional dependencies are known to hold: AB → CD, DE → P, C → E, P → C and B → G. The relational schema R is |
Discuss |
Answer: (d).not in 2NF
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69. | Which option is true about the SQL query given below? SELECT firstName, lastName FROM Employee WHERE lastName BETWEEN 'A%' AND 'D%'; |
Discuss |
Answer: (a).It will display all the employees having last names starting with the alphabets 'A' till 'D' inclusive of A and exclusive of D.
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70. | Which of the given options define a transaction correctly? |
Discuss |
Answer: (c).A transaction consists of either a collection of DML statements or a DDL or DCL or TCL statement to form a logical unit of work in a database session.
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