Recognizing PL/SQL Lexical Units

1) What is a lexical unit?
*A building block of a PL/SQL block

2)Which of the following are lexical units? (Choose two.)
*Literals
*Identifiers

3)Which of the following is a valid naming convention for an identifier? (Choose two.)
*Cannot contain a reserved word
*Can include letters or numbers

4)The name of a variable is an example of an identifier. True or False?
*true

5)What characters must enclose non-numeric literal values?
*Single quotes: ' '

6) Which of the following symbols can be used to enclose a comment in PL/SQL?
*./* */