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Sunday, August 11, 2019

Answer Section 2 Quiz Database Programming with PL/SQL 2019 Learner - English


Section 2


Code is easier to read if you declare one identifier per line. True or False? 
                                               
                True (*)

                                               
                False


                                                                              
If you are using the %TYPE attribute, you can avoid hard coding the:    
                                                                               
                                               
                Column name

                                               
                Data type (*)

                                               
                Table name

                                               
                Constraint

                                                                               
                                                               
Using implicit conversions is good programming practice.   

                                               
                True

                                               
                False (*)

                                                                               
Examine the following code. What is the final value of V_MYVAR ?
DECLARE
    v_myvar NUMBER;
BEGIN
    v_myvar := 1 + 2 * 3;
    v_myvar := v_myvar * 2;
END;
                                                               
                                               
                18

                                               
                81

                                               
                49

                                               
                14 (*)

                                                                               
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;
                                                          
                                               
                v_date := FROM_CHAR(v_char,'dd-Mon-YYYY');

                                               
                v_date := v_char;

                                               
                v_date := TO_DATE(v_char,'dd-Mon-YYYY'); (*)


Which of the following are lexical units? (Choose two.)  
                                                                               
                                               
                PL/SQL blocks

                                               
                Data types

                                               
                Literals (*)

                                               
                Identifiers (*)

                                                                               
Valid identifiers begin with a _____.     
                                                                               
                                               
                Letter (*)

                                               
                Number

                                               
                Special character

                                                                               
                                                               
A datatype may specify a valid range of values. True or False?    

                                               
                True (*)

                                               
                False

                                                                               
                                                               
Which statement most closely describes "data type"?   
                                                                               
                                               
                It is the value of a variable.

                                               
                It is used to test if errors have occurred.

                                               
                It specifies a storage format, constraints, and a valid range of values for a variable. (*)

                                               
                It allows different kinds of data to be stored in a single variable.

                                                                               
                                                               
Two variables with the same name can be declared in an outer block and an inner block. True or False                                                           
                                               
                True (*)

                                               
                False

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;
                                                             
                                               
                ChangChang

                                               
                Chang (*)

                                               
                SusanChang

                                               
                Susan

                                               
                The code will fail with an error

                                                                               
                                                               
Variables can be used in the following ways in a PL/SQL block. (Choose two.)     

                                               
                To refer to a single data value several times. (*)

                                               
                To rename tables and columns.

                                               
                To comment code.

                                               
                To store data values. (*)

                                                                               
                                                               
Which of the following are required when declaring a variable? (Choose two.)   
                                                                               
                                               
                CONSTANT

                                               
                Data type (*)

                                               
                NOT NULL

                                               
                Identifier name (*)

                                                                               
                                                               
Which of the following will help to make code easier to read?    
                                                                               
                                               
                Including comments in the code. (*)

                                               
                Using %Type.

                                               
                Naming variables.

                                                                               
                                                               
Examine the following code:
DECLARE
v_first_name varchar2 (30);
v_salary number (10);
BEGIN
SELECT first_name, salary
INTO v_first_name, v_salary
FROM employees
WHERE last_name = 'King';
END;

Which programming guideline would improve this code?
                                                                  
                                               
                Use a suitable naming convention for variables.

                                               
                Use upper and lower case consistently.

                                               
                Indent the code to make it more readable. (*)

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