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Adding comments
Build a PL/SQL block using SQL*Plus
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To connect to the database, type a valid user name, password, and service. Type PETSTORE in the User Name box. Type
GREATPETS in the Password box. Type MYDB in the Host String box. Click the OK button.
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To display the result of the PL/SQL block on the screen, set the server output on. Type the following command at the SQL >
prompt:
SET SERVEROUTPUT ON
End your SET command by clicking ENTER key. This tells SQL*Plus to execute the command.
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Next, begin the main block with the DECLARE statement. Type DECLARE at the SQL > prompt. End your command by
clicking Enter. This tells SQL*Plus to move to the next line.
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Next, declare a variable of type NUMBER and call it v_num. Type v_num NUMBER; at the 2 prompt. End your
command by clicking Enter. This tells SQL*Plus to move to the next line.
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Start the executable section of the block. Type BEGIN at the 3 prompt. End your command by clicking Enter. This tells
SQL*Plus to move to the next line.
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Assign the value of 42 to v_num. Type v_num := 42; at the 4 prompt. End your command by clicking ENTER. This
tells SQL*Plus to move to the next line.
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Next, add a comment to start the nested block. Type /* Start nested block */ at the 5 prompt. End your command by clicking
ENTER. This tells SQL*Plus to move to the next line.
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Next, declare the nested block. Type DECLARE at the 6 prompt. End your command by clicking ENTER. This tells SQL*Plus to
move to the next line.
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Declare v_char as a VARCHAR2(10) variable that you will use at a later stage to convert the number to a string.
Type v_char VARCHAR2(10); at the 7 prompt. End your command by clicking ENTER. This tells SQL*Plus to move to the next
line.
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Start the executable section of the nested block. Type BEGIN at the 8 prompt. End your command by clicking ENTER. This
tells SQL*Plus to move to the next line.
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Convert the numeric value (v_num) to a character string using the TO_CHAR function and assign it to
v_char. Type v_char := TO_CHAR(v_num); at the 9 prompt. End your command by clicking ENTER. This tells SQL*Plus
to move to the next line.
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Display the string value using the DBMS_OUTPUT.PUT_LINE package procedure. Type DBMS_OUTPUT.PUT_LINE (v_char); at
the 10 prompt. End your command by clicking ENTER. This tells SQL*Plus to move to the next line.
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End the nested block. Type END; at the 11 prompt. End your command by clicking ENTER. This tells SQL*Plus to move to the
next line.
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End the main block. Type END; at the 12 prompt. End your command by clicking ENTER. This tells SQL*Plus to move to the
next line.
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Type / at the 13 prompt for SQL*Plus to compile your PL/SQL block. End your command by clicking ENTER.
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SQL*Plus now displays the result of the compilation of your block.
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