Databases MCQ with Answers

Databases MCQ with Answers

92) Let r be a relation instance with schema R = (A, B, C, D). We define r1 =∏ A,B,C (r) and r2 = ∏A, D(r)
Let S = r1* r2 where * denotes natural join. Given that the decomposition of r into r1 and r2 is lossy, which one of the following is TRUE?

Answer is:

r ⊂ s

93) Let E1 and E2 be two entities in an E/R diagram with simple single-valued attributes. R1 and R2 are two relationships between E1 and E2, where R1 is one-to-many and R2 is many-to-many. RI and R2 do not have any attributes of their own. What is the minimum number of tables required to represent this situation in the relational model?

Answer is:

3

94) The file organization that provides very fast access to any arbitrary record of a file is

Answer is:

Hashed file

95) The physical location of a record is determined by a mathematical formula that transforms a file key into a record location is :

Answer is:

Hashed File

96) A B-tree of order m has maximum of _____________ children

Answer is:

m

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