Oracle Database: Advanced PL/SQL — Question 20

Which two are true about lexical units? (Choose two.)

Answer options

• A. Character literals are case-sensitive.
• B. Spaces can be embedded in delimiters.
• C. Identifiers include labels.
• D. A character literal with zero characters has the BOOLEAN value NULL.
• E. All user-defined identifiers must start with an alphabet.

Correct answer: A, C

Explanation

Option A is correct because character literals are indeed case-sensitive, meaning 'a' and 'A' are treated as distinct values. Option C is also correct as identifiers can include labels, which are a form of identifier. The other options are incorrect as B suggests an incorrect rule about delimiters, D incorrectly states the value of a zero-length character literal, and E is inaccurate since identifiers can begin with underscores or other characters depending on the language rules.