Civil Engineering MCQJE Level Civil Engineering
During an RRB JE solution review on Database, what is the safest statement about primary key? Avoid the common trap that primary key must be duplicated in every row.
Computer ApplicationsDatabaseMEDIUM
Choose the correct answer
A
a primary key uniquely identifies a record in a table
B
primary key must be duplicated in every row
C
primary key is always null
D
primary key stores only images
Correct Answer
A. a primary key uniquely identifies a record in a table
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Primary keys enforce entity identity. Correct option: A.
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This MCQ belongs to RRB JE Civil & Allied Engineering CBT-2 Full Mock Test Series. Full tests include timed attempts, rank comparison and subject-wise analysis.