Civil Engineering MCQJE Level Civil Engineering
A field engineer is checking primary key. Which technical note should be accepted? Avoid the common trap that primary key stores only images.
Computer ApplicationsDatabaseMEDIUM
Choose the correct answer
A
primary key is always null
B
a primary key uniquely identifies a record in a table
C
primary key must be duplicated in every row
D
primary key stores only images
Correct Answer
B. a primary key uniquely identifies a record in a table
AI Detailed Explanation & IS Code Reference
Unlock the reasoning, formula path and code-linked notes inside your student dashboard.
Primary keys enforce entity identity. Correct option: B.
ScoreCardAI links this solution with subject, topic and difficulty signals so your scorecard can identify weak areas after a full mock test.
Concept shortcut
IS/IRC reference
Common trap
Practice more Civil Engineering questions
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.