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Section 2 Quiz (Answer all questions in this section) 1. Which statements about lexical units are true? (Choose two.)

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(Choose all correct answers) They are sequences of characters including letters, digits, tabs, returns and symbols (*) They are optional but can make a PL/SQL block execute faster They are the building blocks of every PL/SQL program (*) They are named objects stored in the database Correct 2. What is a lexical unit?

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A data type for a column A building block of a PL/SQL block (*) A type of variable Correct 3. What will be displayed when the following code is executed? DECLARE x VARCHAR2(6) := 'Chang'; BEGIN DECLARE x VARCHAR2(12) := 'Susan'; BEGIN x := x || x; END; DBMS_OUTPUT.PUT_LINE(x); END; Susan Chang (*) The code will fail with an error ChangChang SusanChang Correct

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4. A variable defined in an outer block is global to the outer block and local to the inner block. True or False?

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True False (*) Correct 5. Is the following variable declaration correct or not?

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DECLARE maxsalary NUMBER(7) = 5000; Correct. Not correct. (*) Incorrect. Refer to Section 2 Lesson 1. 6. Examine the following variable declarations:

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DECLARE v_number NUMBER := 10; v_result NUMBER; Which of the following correctly assigns the value 50 to V_RESULT? All of these are correct (*) v_result := 100 / 2; v_result := ROUND(49.77); v_result := v_number * 5; Incorrect. Refer to Section 2 Lesson 1. 7. The implicit data type conversion at Point A may not work correctly. Why not? DECLARE v_mydate DATE;

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BEGIN V_MYDATE := '29-Feb-2004'; -- Point A END; V_MYDATE has been entered in uppercase Oracle cannot implicitly convert a character string to a date, even if the string contains a valid date value (*) There are only 28 days in February If the database language is not English, 'Feb' has no meaning. Incorrect. Refer to Section 2 Lesson 5. 8. Which of the following are valid PL/SQL operators? (Choose three.)

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(Choose all correct answers) Exponential (*) Arithmetic (*) Concatenation (*) Exception Correct 9. Examine the following block. What should be coded at Line A? DECLARE v_char VARCHAR2(8) := '24-Sep-2007'; v_date DATE; BEGIN v_date := ....... Line A END;

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v_date := TO_DATE(v_char,'dd-Mon-YYYY'); (*) v_date := v_char; v_date := FROM_CHAR(v_char,'dd-Mon-YYYY'); Correct 10. Which of the following is a composite data type?

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DATE VARCHAR2 CLOB

RECORD (*) Correct 11. Which statement most closely describes "data type"?

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It allows different kinds of data to be stored in a single variable. It is the value of a variable. It specifies a storage format, constraints, and a valid range of values for a variable. (*) It is used to test if errors have occurred. Correct 12. Which of the following makes PL/SQL code easier to read and maintain?

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Type everything in lowercase. Place multiple statements on the same line. Use suitable comments in the code. (*) Incorrect. Refer to Section 2 Lesson 7. 13. Which of the following are examples of good programming practice? (Choose three.)

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(Choose all correct answers) Develop naming conventions for identifiers and other objects. (*) Indent code so that it can be read more easily. (*) Document code with comments. (*) Use implicit data type conversions. Use table column names as the names of variables. Incorrect. Refer to Section 2 Lesson 7. 14. You need to declare a variable to hold a value which has been read from the SALARY column of the EMPLOYEES table. Which of the following is an advantage of declaring the variable as: employees.salary%TYPE ?

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If the SALARY column is ALTERed later, the PL/SQL code need not be changed. (*) It is shorter than coding NUMBER(8,2) It executes much faster than using NUMBER(8,2) It allows the software to perform implicit data type conversions. Correct 15. Which of the following is NOT a character data type?

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LONG BOOLEAN (*) CHAR VARCHAR2 Correct