Tài liệu Oracle PL/SQL by Example- P15 pptx

Consider the partial output produced by this script:
Deleted 1 rows for course 10
section_id: 80
===============================
Deleted 4 rows for course 20
section_id: 81
section_id: 82
section_id: 83
section_id: 84
===============================
Deleted 9 rows for course 25
section_id: 85
section_id: 86
section_id: 87
section_id: 88
section_id: 89
section_id: 90
section_id: 91
section_id: 92
section_id: 93
===============================
Deleted 5 rows for course 100
section_id: 141
section_id: 142
section_id: 143
section_id: 144
section_id: 145
===============================
Deleted 6 rows for course 120
section_id: 146
section_id: 147

section_id: 148
section_id: 149
section_id: 150
section_id: 151
===============================
Deleted 5 rows for course 122
section_id: 152
section_id: 153
section_id: 154
section_id: 155
section_id: 156
===============================

PL/SQL procedure successfully completed.
APPENDIX D: Answers to the Try it Yourself Sections
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Chapter 19,“Procedures”
PART 1
1) Write a procedure with no parameters.The procedure should say whether the current day is a
weekend or weekday. Additionally, it should tell you the user’s name and the current time. It also
should specify how many valid and invalid procedures are in the database.
ANSWER: The procedure should look similar to the following:
CREATE OR REPLACE PROCEDURE current_status
AS
v_day_type CHAR(1);
v_user VARCHAR2(30);
v_valid NUMBER;
v_invalid NUMBER;
BEGIN

SELECT SUBSTR(TO_CHAR(sysdate, 'DAY'), 0, 1)
INTO v_day_type
FROM dual;
IF v_day_type = 'S' THEN
DBMS_OUTPUT.PUT_LINE ('Today is a weekend.');
ELSE
DBMS_OUTPUT.PUT_LINE ('Today is a weekday.');
END IF;

DBMS_OUTPUT.PUT_LINE('The time is: '||
TO_CHAR(sysdate, 'HH:MI AM'));

SELECT user
INTO v_user
FROM dual;
DBMS_OUTPUT.PUT_LINE ('The current user is '||v_user);

SELECT NVL(COUNT(*), 0)
INTO v_valid
FROM user_objects
WHERE status = 'VALID'
AND object_type = 'PROCEDURE';
DBMS_OUTPUT.PUT_LINE
('There are '||v_valid||' valid procedures.');

SELECT NVL(COUNT(*), 0)
INTO v_invalid
FROM user_objects
WHERE status = 'INVALID'
AND object_type = 'PROCEDURE';

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DBMS_OUTPUT.PUT_LINE
('There are '||v_invalid||' invalid procedures.');
END;
SET SERVEROUTPUT ON
EXEC current_status;
2)
Write a procedure that takes in a zip code, city, and state and inserts the values into the zip code
table. It should check to see if the zip code is already in the database. If it is, an exception should
be raised, and an error message should be displayed.Write an anonymous block that uses the
procedure and inserts your zip code.
ANSWER: The script should look similar to the following:
CREATE OR REPLACE PROCEDURE insert_zip
(I_ZIPCODE IN zipcode.zip%TYPE,
I_CITY IN zipcode.city%TYPE,
I_STATE IN zipcode.state%TYPE)
AS
v_zipcode zipcode.zip%TYPE;
v_city zipcode.city%TYPE;
v_state zipcode.state%TYPE;
v_dummy zipcode.zip%TYPE;
BEGIN
v_zipcode := i_zipcode;
v_city := i_city;
v_state := i_state;

SELECT zip
INTO v_dummy

FROM zipcode
WHERE zip = v_zipcode;

DBMS_OUTPUT.PUT_LINE('The zipcode '||v_zipcode||
' is already in the database and cannot be'||
' reinserted.');

EXCEPTION
WHEN NO_DATA_FOUND THEN
INSERT INTO ZIPCODE
VALUES (v_zipcode, v_city, v_state, user, sysdate,
user, sysdate);
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE ('There was an unknown error '||
'in insert_zip.');
END;
SET SERVEROUTPUT ON
BEGIN
insert_zip (10035, 'No Where', 'ZZ');
END;
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BEGIN
insert_zip (99999, 'No Where', 'ZZ');
END;
ROLLBACK;
PART 2
1) Create a stored procedure based on the script ch17_1c.sql, version 3.0, created in Lab 17.1 of
Chapter 17.The procedure should accept two parameters to hold a table name and an ID and

should return six parameters with first name, last name, street, city, state, and zip code information.
ANSWER: The procedure should look similar to the following. Changes are shown in bold.
CREATE OR REPLACE PROCEDURE get_name_address
(table_name_in IN VARCHAR2
,id_in IN NUMBER
,first_name_out OUT VARCHAR2
,last_name_out OUT VARCHAR2
,street_out OUT VARCHAR2
,city_out OUT VARCHAR2
,state_out OUT VARCHAR2
,zip_out OUT VARCHAR2)
AS
sql_stmt VARCHAR2(200);
BEGIN
sql_stmt := 'SELECT a.first_name, a.last_name, a.street_address'||
' ,b.city, b.state, b.zip' ||
' FROM '||table_name_in||' a, zipcode b' ||
' WHERE a.zip = b.zip' ||
' AND '||table_name_in||'_id = :1';
EXECUTE IMMEDIATE sql_stmt
INTO first_name_out, last_name_out, street_out, city_out,
state_out, zip_out
USING id_in;
END get_name_address;
This procedure contains two IN parameters whose values are used by the dynamic SQL statement
and six OUT parameters that hold data returned by the SELECT statement. After it is created, this
procedure can be tested with the following PL/SQL block:
SET SERVEROUTPUT ON
DECLARE
v_table_name VARCHAR2(20) := '&sv_table_name';

v_id NUMBER := &sv_id;
v_first_name VARCHAR2(25);
v_last_name VARCHAR2(25);
v_street VARCHAR2(50);
v_city VARCHAR2(25);
v_state VARCHAR2(2);
v_zip VARCHAR2(5);
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BEGIN
get_name_address (v_table_name, v_id, v_first_name, v_last_name,
v_street, v_city, v_state, v_zip);
DBMS_OUTPUT.PUT_LINE ('First Name: '||v_first_name);
DBMS_OUTPUT.PUT_LINE ('Last Name: '||v_last_name);
DBMS_OUTPUT.PUT_LINE ('Street: '||v_street);
DBMS_OUTPUT.PUT_LINE ('City: '||v_city);
DBMS_OUTPUT.PUT_LINE ('State: '||v_state);
DBMS_OUTPUT.PUT_LINE ('Zip Code: '||v_zip);
END;
When run, this script produces the following output. The first run is against the STUDENT table,
and the second run is against the INSTRUCTOR table.
Enter value for sv_table_name: student
old 2: v_table_name VARCHAR2(20) := '&sv_table_name';
new 2: v_table_name VARCHAR2(20) := 'student';
Enter value for sv_id: 105
old 3: v_id NUMBER := &sv_id;
new 3: v_id NUMBER := 105;
First Name: Angel
Last Name: Moskowitz

Street: 320 John St.
City: Ft. Lee
State: NJ
Zip Code: 07024
PL/SQL procedure successfully completed.
Enter value for sv_table_name: instructor
old 2: v_table_name VARCHAR2(20) := '&sv_table_name';
new 2: v_table_name VARCHAR2(20) := 'instructor';
Enter value for sv_id: 105
old 3: v_id NUMBER := &sv_id;
new 3: v_id NUMBER := 105;
First Name: Anita
Last Name: Morris
Street: 34 Maiden Lane
City: New York
State: NY
Zip Code: 10015
PL/SQL procedure successfully completed.
2)
Modify the procedure you just created. Instead of using six parameters to hold name and address
information, the procedure should return a user-defined record that contains six fields that hold
name and address information. Note: You may want to create a package in which you define a
record type.This record may be used later, such as when the procedure is invoked in a PL/SQL
block.
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ANSWER: The package should look similar to the following. Changes are shown in bold.
CREATE OR REPLACE PACKAGE dynamic_sql_pkg
AS

Create user-defined record type
TYPE name_addr_rec_type IS RECORD
(first_name VARCHAR2(25),
last_name VARCHAR2(25),
street VARCHAR2(50),
city VARCHAR2(25),
state VARCHAR2(2),
zip VARCHAR2(5));
PROCEDURE get_name_address (table_name_in IN VARCHAR2
,id_in IN NUMBER
,name_addr_rec OUT name_addr_rec_type);
END dynamic_sql_pkg;
/
CREATE OR REPLACE PACKAGE BODY dynamic_sql_pkg AS
PROCEDURE get_name_address (table_name_in IN VARCHAR2
,id_in IN NUMBER
,name_addr_rec OUT name_addr_rec_type)
IS
sql_stmt VARCHAR2(200);
BEGIN
sql_stmt := 'SELECT a.first_name, a.last_name, a.street_address'||
' ,b.city, b.state, b.zip' ||
' FROM '||table_name_in||' a, zipcode b' ||
' WHERE a.zip = b.zip' ||
' AND '||table_name_in||'_id = :1';
EXECUTE IMMEDIATE sql_stmt
INTO name_addr_rec
USING id_in;
END get_name_address;
END dynamic_sql_pkg;

/
In this package specification, you declare a user-defined record type.The procedure uses this
record type for its OUT parameter, name_addr_rec. After the package is created, its procedure
can be tested with the following PL/SQL block (changes are shown in bold):
SET SERVEROUTPUT ON
DECLARE
v_table_name VARCHAR2(20) := '&sv_table_name';
v_id NUMBER := &sv_id;
name_addr_rec DYNAMIC_SQL_PKG.NAME_ADDR_REC_TYPE;
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BEGIN
dynamic_sql_pkg.get_name_address (v_table_name, v_id,
name_addr_rec);
DBMS_OUTPUT.PUT_LINE ('First Name: '||name_addr_rec.first_name);
DBMS_OUTPUT.PUT_LINE ('Last Name: '||name_addr_rec.last_name);
DBMS_OUTPUT.PUT_LINE ('Street: '||name_addr_rec.street);
DBMS_OUTPUT.PUT_LINE ('City: '||name_addr_rec.city);
DBMS_OUTPUT.PUT_LINE ('State: '||name_addr_rec.state);
DBMS_OUTPUT.PUT_LINE ('Zip Code: '||name_addr_rec.zip);
END;
Notice that instead of declaring six variables, you declare one variable of the user-defined record
type, name_addr_rec_type. Because this record type is defined in the package
DYNAMIC_SQL_PKG, the name of the record type is prefixed with the name of the package.
Similarly, the name of the package is added to the procedure call statement.
When run, this script produces the following output. The first output is against the STUDENT table,
and the second output is against the INSTRUCTOR table.
Enter value for sv_table_name: student
old 2: v_table_name VARCHAR2(20) := '&sv_table_name';

new 2: v_table_name VARCHAR2(20) := 'student';
Enter value for sv_id: 105
old 3: v_id NUMBER := &sv_id;
new 3: v_id NUMBER := 105;
First Name: Angel
Last Name: Moskowitz
Street: 320 John St.
City: Ft. Lee
State: NJ
Zip Code: 07024
PL/SQL procedure successfully completed.
Enter value for sv_table_name: instructor
old 2: v_table_name VARCHAR2(20) := '&sv_table_name';
new 2: v_table_name VARCHAR2(20) := 'instructor';
Enter value for sv_id: 105
old 3: v_id NUMBER := &sv_id;
new 3: v_id NUMBER := 105;
First Name: Anita
Last Name: Morris
Street: 34 Maiden Lane
City: New York
State: NY
Zip Code: 10015
PL/SQL procedure successfully completed.
APPENDIX D: Answers to the Try it Yourself Sections
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Chapter 20,“Functions”
1) Write a stored function called new_student_id that takes in no parameters and returns a
student.student_id%TYPE.The value returned will be used when inserting a new

student into the CTA application. It will be derived by using the formula student_id_seq.
NEXTVAL
.
ANSWER: The function should look similar to the following:
CREATE OR REPLACE FUNCTION new_student_id
RETURN student.student_id%TYPE
AS
v_student_id student.student_id%TYPE;
BEGIN
SELECT student_id_seq.NEXTVAL
INTO v_student_id
FROM dual;
RETURN(v_student_id);
END;
2)
Write a stored function called zip_does_not_exist that takes in a zipcode.
zip%TYPE
and returns a Boolean.The function will return TRUE if the zip code passed into it
does not exist. It will return a FALSE if the zip code does exist. Hint: Here’s an example of how this
might be used:
DECLARE
cons_zip CONSTANT zipcode.zip%TYPE := '&sv_zipcode';
e_zipcode_is_not_valid EXCEPTION;
BEGIN
IF zipcode_does_not_exist(cons_zip)
THEN
RAISE e_zipcode_is_not_valid;
ELSE
An insert of an instructor's record which
makes use of the checked zipcode might go here.

NULL;
END IF;
EXCEPTION
WHEN e_zipcode_is_not_valid THEN
RAISE_APPLICATION_ERROR
(-20003, 'Could not find zipcode '||cons_zip||'.');
END;
ANSWER:
The function should look similar to the following:
CREATE OR REPLACE FUNCTION zipcode_does_not_exist
(i_zipcode IN zipcode.zip%TYPE)
RETURN BOOLEAN
AS
v_dummy char(1);
BEGIN
SELECT NULL
INTO v_dummy
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FROM zipcode
WHERE zip = i_zipcode;
Meaning the zipcode does exit
RETURN FALSE;
EXCEPTION
WHEN OTHERS THEN
The select statement above will cause an exception
to be raised if the zipcode is not in the database.
RETURN TRUE;
END zipcode_does_not_exist;

3)
Create a new function. For a given instructor, determine how many sections he or she is teaching.
If the number is greater than or equal to 3, return a message saying that the instructor needs a
vacation. Otherwise, return a message saying how many sections this instructor is teaching.
ANSWER: The function should look similar to the following:
CREATE OR REPLACE FUNCTION instructor_status
(i_first_name IN instructor.first_name%TYPE,
i_last_name IN instructor.last_name%TYPE)
RETURN VARCHAR2
AS
v_instructor_id instructor.instructor_id%TYPE;
v_section_count NUMBER;
v_status VARCHAR2(100);
BEGIN
SELECT instructor_id
INTO v_instructor_id
FROM instructor
WHERE first_name = i_first_name
AND last_name = i_last_name;
SELECT COUNT(*)
INTO v_section_count
FROM section
WHERE instructor_id = v_instructor_id;
IF v_section_count >= 3 THEN
v_status :=
'The instructor '||i_first_name||' '||
i_last_name||' is teaching '||v_section_count||
' and needs a vaction.';
ELSE
v_status :=

'The instructor '||i_first_name||' '||
i_last_name||' is teaching '||v_section_count||
' courses.';
END IF;
RETURN v_status;
EXCEPTION
WHEN NO_DATA_FOUND THEN
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Note that either of the SELECT statements can raise
this exception
v_status :=
'The instructor '||i_first_name||' '||
i_last_name||' is not shown to be teaching'||
' any courses.';
RETURN v_status;
WHEN OTHERS THEN
v_status :=
'There has been in an error in the function.';
RETURN v_status;
END;
Test the function as follows:
SELECT instructor_status(first_name, last_name)
FROM instructor;
/
Chapter 21,“Packages”
1) Add a procedure to the student_api package called remove_student.This procedure
accepts a student_id and returns nothing. Based on the student ID passed in, it removes the
student from the database. If the student does not exist or if a problem occurs while removing the

student (such as a foreign key constraint violation), let the calling program handle it.
ANSWER: The package should be similar to the following:
CREATE OR REPLACE PACKAGE student_api AS
v_current_date DATE;
PROCEDURE discount;
FUNCTION new_instructor_id
RETURN instructor.instructor_id%TYPE;
FUNCTION total_cost_for_student
(p_student_id IN student.student_id%TYPE)
RETURN course.cost%TYPE;
PRAGMA RESTRICT_REFERENCES
(total_cost_for_student, WNDS, WNPS, RNPS);
PROCEDURE get_student_info
(p_student_id IN student.student_id%TYPE,
p_last_name OUT student.last_name%TYPE,
p_first_name OUT student.first_name%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER);
PROCEDURE get_student_info
(p_last_name IN student.last_name%TYPE,
p_first_name IN student.first_name%TYPE,
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p_student_id OUT student.student_id%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER);
PROCEDURE remove_student
(p_studid IN student.student_id%TYPE);
END student_api;

/
CREATE OR REPLACE PACKAGE BODY student_api AS
PROCEDURE discount
IS
CURSOR c_group_discount IS
SELECT distinct s.course_no, c.description
FROM section s, enrollment e, course c
WHERE s.section_id = e.section_id
GROUP BY s.course_no, c.description,
e.section_id, s.section_id
HAVING COUNT(*) >=8;
BEGIN
FOR r_group_discount IN c_group_discount LOOP
UPDATE course
SET cost = cost * .95
WHERE course_no = r_group_discount.course_no;
DBMS_OUTPUT.PUT_LINE
('A 5% discount has been given to'||
r_group_discount.course_no||' '||
r_group_discount.description);
END LOOP;
END discount;
FUNCTION new_instructor_id
RETURN instructor.instructor_id%TYPE
IS
v_new_instid instructor.instructor_id%TYPE;
BEGIN
SELECT INSTRUCTOR_ID_SEQ.NEXTVAL
INTO v_new_instid
FROM dual;

RETURN v_new_instid;
EXCEPTION
WHEN OTHERS THEN
DECLARE
v_sqlerrm VARCHAR2(250) := SUBSTR(SQLERRM,1,250);
BEGIN
RAISE_APPLICATION_ERROR
(-20003, 'Error in instructor_id: '||v_sqlerrm);
END;
END new_instructor_id;
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FUNCTION get_course_descript_private
(p_course_no course.course_no%TYPE)
RETURN course.description%TYPE
IS
v_course_descript course.description%TYPE;
BEGIN
SELECT description
INTO v_course_descript
FROM course
WHERE course_no = p_course_no;
RETURN v_course_descript;
EXCEPTION
WHEN OTHERS THEN
RETURN NULL;
END get_course_descript_private;
FUNCTION total_cost_for_student
(p_student_id IN student.student_id%TYPE)

RETURN course.cost%TYPE
IS
v_cost course.cost%TYPE;
BEGIN
SELECT sum(cost)
INTO v_cost
FROM course c, section s, enrollment e
WHERE c.course_no = c.course_no
AND e.section_id = s.section_id
AND e.student_id = p_student_id;
RETURN v_cost;
EXCEPTION
WHEN OTHERS THEN
RETURN NULL;
END total_cost_for_student;
PROCEDURE get_student_info
(p_student_id IN student.student_id%TYPE,
p_last_name OUT student.last_name%TYPE,
p_first_name OUT student.first_name%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER)
IS
BEGIN
SELECT last_name, first_name, zip
INTO p_last_name, p_first_name, p_zip
FROM student
WHERE student.student_id = p_student_id;
p_return_code := 0;
EXCEPTION
WHEN NO_DATA_FOUND THEN

DBMS_OUTPUT.PUT_LINE ('Student ID is not valid.');
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p_return_code := -100;
p_last_name := NULL;
p_first_name := NULL;
p_zip := NULL;
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE
('Error in procedure get_student_info');
END get_student_info;
PROCEDURE get_student_info
(p_last_name IN student.last_name%TYPE,
p_first_name IN student.first_name%TYPE,
p_student_id OUT student.student_id%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER)
IS
BEGIN
SELECT student_id, zip
INTO p_student_id, p_zip
FROM student
WHERE UPPER(last_name) = UPPER(p_last_name)
AND UPPER(first_name) = UPPER(p_first_name);
p_return_code := 0;
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE ('Student name is not valid.');
p_return_code := -100;

p_student_id := NULL;
p_zip := NULL;
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE
('Error in procedure get_student_info');
END get_student_info;
PROCEDURE remove_student
(p_studid IN student.student_id%TYPE)
IS
BEGIN
DELETE
FROM STUDENT
WHERE student_id = p_studid;
END;
BEGIN
SELECT trunc(sysdate, 'DD')
INTO v_current_date
FROM dual;
END student_api;
/
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2) Alter remove_student in the student_api package body to accept an additional param-
eter.This new parameter should be a VARCHAR2 and called p_ri. Make p_ri default to R.The
new parameter may contain a value of R or C. If R is received, it represents DELETE RESTRICT,
and the procedure acts as it does now. If there are enrollments for the student, the delete is
disallowed. If a C is received, it represents DELETE CASCADE. This functionally means that the
remove_student procedure locates all records for the student in all the tables. It removes
them from the database before attempting to remove the student from the student table. Decide

how to handle the situation when the user passes in a code other than C or R.
ANSWER: The package should look similar to the following:
CREATE OR REPLACE PACKAGE student_api AS
v_current_date DATE;
PROCEDURE discount;
FUNCTION new_instructor_id
RETURN instructor.instructor_id%TYPE;
FUNCTION total_cost_for_student
(p_student_id IN student.student_id%TYPE)
RETURN course.cost%TYPE;
PRAGMA RESTRICT_REFERENCES
(total_cost_for_student, WNDS, WNPS, RNPS);
PROCEDURE get_student_info
(p_student_id IN student.student_id%TYPE,
p_last_name OUT student.last_name%TYPE,
p_first_name OUT student.first_name%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER);
PROCEDURE get_student_info
(p_last_name IN student.last_name%TYPE,
p_first_name IN student.first_name%TYPE,
p_student_id OUT student.student_id%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER);
PROCEDURE remove_student
(p_studid IN student.student_id%TYPE,
p_ri IN VARCHAR2 DEFAULT 'R');
END student_api;
/
CREATE OR REPLACE PACKAGE BODY student_api AS

PROCEDURE discount
IS
CURSOR c_group_discount IS
SELECT distinct s.course_no, c.description
FROM section s, enrollment e, course c
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WHERE s.section_id = e.section_id
GROUP BY s.course_no, c.description,
e.section_id, s.section_id
HAVING COUNT(*) >=8;
BEGIN
FOR r_group_discount IN c_group_discount LOOP
UPDATE course
SET cost = cost * .95
WHERE course_no = r_group_discount.course_no;
DBMS_OUTPUT.PUT_LINE
('A 5% discount has been given to'||
r_group_discount.course_no||' '||
r_group_discount.description);
END LOOP;
END discount;
FUNCTION new_instructor_id
RETURN instructor.instructor_id%TYPE
IS
v_new_instid instructor.instructor_id%TYPE;
BEGIN
SELECT INSTRUCTOR_ID_SEQ.NEXTVAL
INTO v_new_instid

FROM dual;
RETURN v_new_instid;
EXCEPTION
WHEN OTHERS THEN
DECLARE
v_sqlerrm VARCHAR2(250) := SUBSTR(SQLERRM,1,250);
BEGIN
RAISE_APPLICATION_ERROR
(-20003, 'Error in instructor_id: '||v_sqlerrm);
END;
END new_instructor_id;
FUNCTION get_course_descript_private
(p_course_no course.course_no%TYPE)
RETURN course.description%TYPE
IS
v_course_descript course.description%TYPE;
BEGIN
SELECT description
INTO v_course_descript
FROM course
WHERE course_no = p_course_no;
RETURN v_course_descript;
EXCEPTION
WHEN OTHERS THEN
RETURN NULL;
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END get_course_descript_private;
FUNCTION total_cost_for_student

(p_student_id IN student.student_id%TYPE)
RETURN course.cost%TYPE
IS
v_cost course.cost%TYPE;
BEGIN
SELECT sum(cost)
INTO v_cost
FROM course c, section s, enrollment e
WHERE c.course_no = c.course_no
AND e.section_id = s.section_id
AND e.student_id = p_student_id;
RETURN v_cost;
EXCEPTION
WHEN OTHERS THEN
RETURN NULL;
END total_cost_for_student;
PROCEDURE get_student_info
(p_student_id IN student.student_id%TYPE,
p_last_name OUT student.last_name%TYPE,
p_first_name OUT student.first_name%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER)
IS
BEGIN
SELECT last_name, first_name, zip
INTO p_last_name, p_first_name, p_zip
FROM student
WHERE student.student_id = p_student_id;
p_return_code := 0;
EXCEPTION

WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE ('Student ID is not valid.');
p_return_code := -100;
p_last_name := NULL;
p_first_name := NULL;
p_zip := NULL;
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE
('Error in procedure get_student_info');
END get_student_info;
PROCEDURE get_student_info
(p_last_name IN student.last_name%TYPE,
p_first_name IN student.first_name%TYPE,
p_student_id OUT student.student_id%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER)
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IS
BEGIN
SELECT student_id, zip
INTO p_student_id, p_zip
FROM student
WHERE UPPER(last_name) = UPPER(p_last_name)
AND UPPER(first_name) = UPPER(p_first_name);
p_return_code := 0;
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE

('Student name is not valid.');
p_return_code := -100;
p_student_id := NULL;
p_zip := NULL;
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE
('Error in procedure get_student_info');
END get_student_info;
PROCEDURE remove_student
The parameters student_id and p_ri give the user an
option of cascade delete or restrict delete for
the given student's records
(p_studid IN student.student_id%TYPE,
p_ri IN VARCHAR2 DEFAULT 'R')
IS
Declare exceptions for use in procedure
enrollment_present EXCEPTION;
bad_pri EXCEPTION;
BEGIN
R value is for restrict delete option
IF p_ri = 'R' THEN
DECLARE
A variable is needed to test if the student
is in the enrollment table
v_dummy CHAR(1);
BEGIN
This is a standard existence check.
If v_dummy is assigned a value via the
SELECT INTO, the exception
enrollment_present will be raised.

If the v_dummy is not assigned a value, the
exception no_data_found will be raised.
SELECT NULL
INTO v_dummy
FROM enrollment e
WHERE e.student_id = p_studid
AND ROWNUM = 1;
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The rownum set to 1 prevents the SELECT
INTO statement raise to_many_rows
exception.
If there is at least one row in the enrollment
table with a corresponding student_id, the
restrict delete parameter will disallow the
deletion of the student by raising
the enrollment_present exception.
RAISE enrollment_present;
EXCEPTION
WHEN NO_DATA_FOUND THEN
The no_data_found exception is raised
when there are no students found in the
enrollment table. Since the p_ri indicates
a restrict delete user choice the delete
operation is permitted.
DELETE FROM student
WHERE student_id = p_studid;
END;
When the user enters "C" for the p_ri

he/she indicates a cascade delete choice
ELSIF p_ri = 'C' THEN
Delete the student from the enrollment and
grade tables
DELETE FROM enrollment
WHERE student_id = p_studid;
DELETE FROM grade
WHERE student_id = p_studid;
Delete from student table only after corresponding
records have been removed from the other tables
because the student table is the parent table
DELETE FROM student
WHERE student_id = p_studid;
ELSE
RAISE bad_pri;
END IF;
EXCEPTION
WHEN bad_pri THEN
RAISE_APPLICATION_ERROR
(-20231, 'An incorrect p_ri value was '||
'entered. The remove_student procedure can '||
'only accept a C or R for the p_ri parameter.');
WHEN enrollment_present THEN
RAISE_APPLICATION_ERROR
(-20239, 'The student with ID'||p_studid||
' exists in the enrollment table thus records'||
' will not be removed.');
APPENDIX D: Answers to the Try it Yourself Sections
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END remove_student;
BEGIN
SELECT trunc(sysdate, 'DD')
INTO v_current_date
FROM dual;
END student_api;
Chapter 22,“Stored Code”
1) Add a function to the student_api package specification called get_course_
descript
.The caller takes a course.cnumber%TYPE parameter, and it returns a
course.description%TYPE.
ANSWER: The package should look similar to the following:
CREATE OR REPLACE PACKAGE student_api AS
v_current_date DATE;
PROCEDURE discount;
FUNCTION new_instructor_id
RETURN instructor.instructor_id%TYPE;
FUNCTION total_cost_for_student
(p_student_id IN student.student_id%TYPE)
RETURN course.cost%TYPE;
PRAGMA RESTRICT_REFERENCES
(total_cost_for_student, WNDS, WNPS, RNPS);
PROCEDURE get_student_info
(p_student_id IN student.student_id%TYPE,
p_last_name OUT student.last_name%TYPE,
p_first_name OUT student.first_name%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER);
PROCEDURE get_student_info
(p_last_name IN student.last_name%TYPE,

p_first_name IN student.first_name%TYPE,
p_student_id OUT student.student_id%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER);
PROCEDURE remove_student
(p_studid IN student.student_id%TYPE,
p_ri IN VARCHAR2 DEFAULT 'R');
FUNCTION get_course_descript
(p_cnumber course.course_no%TYPE)
RETURN course.description%TYPE;
END student_api;
APPENDIX D: Answers to the Try it Yourself Sections
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2) Create a function in the student_api package body called get_course_description.
A caller passes in a course number, and it returns the course description. Instead of searching for
the description itself, it makes a call to get_course_descript_private. It passes its
course number to get_course_descript_private. It passes back to the caller the
description it gets back from get_course_descript_private.
ANSWER: The package body should look similar to the following:
CREATE OR REPLACE PACKAGE BODY student_api AS
PROCEDURE discount
IS
CURSOR c_group_discount IS
SELECT distinct s.course_no, c.description
FROM section s, enrollment e, course c
WHERE s.section_id = e.section_id
GROUP BY s.course_no, c.description,
e.section_id, s.section_id
HAVING COUNT(*) >=8;

BEGIN
FOR r_group_discount IN c_group_discount LOOP
UPDATE course
SET cost = cost * .95
WHERE course_no = r_group_discount.course_no;
DBMS_OUTPUT.PUT_LINE
('A 5% discount has been given to'||
r_group_discount.course_no||' '||
r_group_discount.description);
END LOOP;
END discount;
FUNCTION new_instructor_id
RETURN instructor.instructor_id%TYPE
IS
v_new_instid instructor.instructor_id%TYPE;
BEGIN
SELECT INSTRUCTOR_ID_SEQ.NEXTVAL
INTO v_new_instid
FROM dual;
RETURN v_new_instid;
EXCEPTION
WHEN OTHERS THEN
DECLARE
v_sqlerrm VARCHAR2(250) := SUBSTR(SQLERRM,1,250);
BEGIN
RAISE_APPLICATION_ERROR
(-20003, 'Error in instructor_id: '||v_sqlerrm);
END;
END new_instructor_id;
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FUNCTION get_course_descript_private
(p_course_no course.course_no%TYPE)
RETURN course.description%TYPE
IS
v_course_descript course.description%TYPE;
BEGIN
SELECT description
INTO v_course_descript
FROM course
WHERE course_no = p_course_no;
RETURN v_course_descript;
EXCEPTION
WHEN OTHERS THEN
RETURN NULL;
END get_course_descript_private;
FUNCTION total_cost_for_student
(p_student_id IN student.student_id%TYPE)
RETURN course.cost%TYPE
IS
v_cost course.cost%TYPE;
BEGIN
SELECT sum(cost)
INTO v_cost
FROM course c, section s, enrollment e
WHERE c.course_no = c.course_no
AND e.section_id = s.section_id
AND e.student_id = p_student_id;
RETURN v_cost;

EXCEPTION
WHEN OTHERS THEN
RETURN NULL;
END total_cost_for_student;
PROCEDURE get_student_info
(p_student_id IN student.student_id%TYPE,
p_last_name OUT student.last_name%TYPE,
p_first_name OUT student.first_name%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER)
IS
BEGIN
SELECT last_name, first_name, zip
INTO p_last_name, p_first_name, p_zip
FROM student
WHERE student.student_id = p_student_id;
p_return_code := 0;
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE ('Student ID is not valid.');
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p_return_code := -100;
p_last_name := NULL;
p_first_name := NULL;
p_zip := NULL;
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE
('Error in procedure get_student_info');

END get_student_info;
PROCEDURE get_student_info
(p_last_name IN student.last_name%TYPE,
p_first_name IN student.first_name%TYPE,
p_student_id OUT student.student_id%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER)
IS
BEGIN
SELECT student_id, zip
INTO p_student_id, p_zip
FROM student
WHERE UPPER(last_name) = UPPER(p_last_name)
AND UPPER(first_name) = UPPER(p_first_name);
p_return_code := 0;
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE ('Student name is not valid.');
p_return_code := -100;
p_student_id := NULL;
p_zip := NULL;
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE
('Error in procedure get_student_info');
END get_student_info;
PROCEDURE remove_student
The parameters student_id and p_ri give the user an
option of cascade delete or restrict delete for
the given student's records
(p_studid IN student.student_id%TYPE,

p_ri IN VARCHAR2 DEFAULT 'R')
IS
Declare exceptions for use in procedure
enrollment_present EXCEPTION;
bad_pri EXCEPTION;
BEGIN
The R value is for restrict delete option
IF p_ri = 'R' THEN
DECLARE
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A variable is needed to test if the student
is in the enrollment table
v_dummy CHAR(1);
BEGIN
This is a standard existence check.
If v_dummy is assigned a value via the
SELECT INTO, the exception
enrollment_present will be raised.
If the v_dummy is not assigned a value, the
exception no_data_found will be raised.
SELECT NULL
INTO v_dummy
FROM enrollment e
WHERE e.student_id = p_studid
AND ROWNUM = 1;
The rownum set to 1 prevents the SELECT
INTO statement raise to_many_rows exception.
If there is at least one row in the enrollment

table with a corresponding student_id, the
restrict delete parameter will disallow
the deletion of the student by raising
the enrollment_present exception.
RAISE enrollment_present;
EXCEPTION
WHEN NO_DATA_FOUND THEN
The no_data_found exception is raised
when no students are found in the
enrollment table.
Since the p_ri indicates a restrict
delete user choice, the delete operation
is permitted.
DELETE FROM student
WHERE student_id = p_studid;
END;
When the user enters "C" for the p_ri
he/she indicates a cascade delete choice
ELSIF p_ri = 'C' THEN
Delete the student from the enrollment and
grade tables
DELETE FROM enrollment
WHERE student_id = p_studid;
DELETE FROM grade
WHERE student_id = p_studid;
Delete from student table only after
corresponding records have been removed from
the other tables because the student table is
the parent table
APPENDIX D: Answers to the Try it Yourself Sections

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DELETE
FROM student
WHERE student_id = p_studid;
ELSE
RAISE bad_pri;
END IF;
EXCEPTION
WHEN bad_pri THEN
RAISE_APPLICATION_ERROR
(-20231, 'An incorrect p_ri value was '||
'entered. The remove_student procedure can '||
'only accept a C or R for the p_ri parameter.');
WHEN enrollment_present THEN
RAISE_APPLICATION_ERROR
(-20239, 'The student with ID'||p_studid||
' exists in the enrollment table thus records'||
' will not be removed.');
END remove_student;
FUNCTION get_course_descript
(p_cnumber course.course_no%TYPE)
RETURN course.description%TYPE
IS
BEGIN
RETURN get_course_descript_private(p_cnumber);
END get_course_descript;
BEGIN
SELECT trunc(sysdate, 'DD')
INTO v_current_date

FROM dual;
END student_api;
3)
Add a PRAGMA RESTRICT_REFERENCES to student_api for get_course_description
specifying the following: It writes no database state, it writes no package state, and it reads no
package state.
ANSWER: The package should look similar to the following:
CREATE OR REPLACE PACKAGE student_api AS
v_current_date DATE;
PROCEDURE discount;
FUNCTION new_instructor_id
RETURN instructor.instructor_id%TYPE;
FUNCTION total_cost_for_student
(p_student_id IN student.student_id%TYPE)
RETURN course.cost%TYPE;
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PRAGMA RESTRICT_REFERENCES
(total_cost_for_student, WNDS, WNPS, RNPS);
PROCEDURE get_student_info
(p_student_id IN student.student_id%TYPE,
p_last_name OUT student.last_name%TYPE,
p_first_name OUT student.first_name%TYPE,
p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER);
PROCEDURE get_student_info
(p_last_name IN student.last_name%TYPE,
p_first_name IN student.first_name%TYPE,
p_student_id OUT student.student_id%TYPE,

p_zip OUT student.zip%TYPE,
p_return_code OUT NUMBER);
PROCEDURE remove_student
(p_studid IN student.student_id%TYPE,
p_ri IN VARCHAR2 DEFAULT 'R');
FUNCTION get_course_descript
(p_cnumber course.course_no%TYPE)
RETURN course.description%TYPE;
PRAGMA RESTRICT_REFERENCES
(get_course_descript,WNDS, WNPS, RNPS);
END student_api;
/
Chapter 23,“Object Types in Oracle”
1) Create the object type student_obj_type with attributes derived from the STUDENT table.
ANSWER: The object type should look similar to the following:
CREATE OR REPLACE TYPE student_obj_type AS OBJECT
(student_id NUMBER(8),
salutation VARCHAR2(5),
first_name VARCHAR2(25),
last_name VARCHAR2(25),
street_address VARCHAR2(50),
zip VARCHAR2(5),
phone VARCHAR2(15),
employer VARCHAR2(50),
registration_date DATE,
created_by VARCHAR2(30),
created_date DATE,
modified_by VARCHAR2(30),
modified_date DATE);
/

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