Tài liệu Oracle PL/SQL by Example- P10 ppt

FOR EXAMPLEDECLARE -- Define collection type and variables to be used by the -- BULK COLLECT clause TYPE student_id_type IS TABLE OF student.student_id%TYPE; TYPE first_name_type IS TABL

L A B 1 8 2

The BULK COLLECT Clause

L A B O B J E C T I V E

After completing this lab, you will be able to

Use the BULK COLLECT clause

The BULK COLLECT clause fetches the batches of results and brings them back from SQL to PL/SQL For example, consider a cursor against the STUDENT table that returns the student’s

ID, first name, and last name After this cursor is opened, the rows are fetched one by one until all of them have been processed Then this cursor is closed These steps are illustrated in the following example:

FOR rec IN student_cur LOOP

DBMS_OUTPUT.PUT_LINE ('student_id: '||rec.student_id);

DBMS_OUTPUT.PUT_LINE ('first_name: '||rec.first_name);

DBMS_OUTPUT.PUT_LINE ('last_name: '||rec.last_name);

END LOOP;

END;

Recall that the cursor FOR loop opens and closes the cursor and fetches cursor records implicitly The same task of fetching records from the STUDENT table can be accomplished by employing the BULK COLLECT clause The difference here is that the BULK COLLECT clause fetches all rows from the STUDENT table at once Because BULK COLLECT fetches multiple rows, these rows are stored in collection variables.

Consider a modified version of the previous example, in which the cursor processing is replaced

by the BULK COLLECT clause:

LAB 18.2

422

FOR EXAMPLE

DECLARE

Define collection type and variables to be used by the

BULK COLLECT clause

TYPE student_id_type IS TABLE OF student.student_id%TYPE;

TYPE first_name_type IS TABLE OF student.first_name%TYPE;

TYPE last_name_type IS TABLE OF student.last_name%TYPE;

student_id_tab student_id_type;

first_name_tab first_name_type;

last_name_tab last_name_type;

BEGIN

Fetch all student data at once via BULK COLLECT clause

SELECT student_id, first_name, last_name

BULK COLLECT INTO student_id_tab, first_name_tab, last_name_tab

FROM student;

FOR i IN student_id_tab.FIRST student_id_tab.LAST

LOOP

DBMS_OUTPUT.PUT_LINE ('student_id: '||student_id_tab(i));

DBMS_OUTPUT.PUT_LINE ('first_name: '||first_name_tab(i));

DBMS_OUTPUT.PUT_LINE ('last_name: '||last_name_tab(i));

END LOOP;

END;

This script declares three nested table types and variables These variables are used to store data returned by the SELECT statement with the BULK COLLECT clause.

DID YOU KNOW?

When nested tables are populated using the SELECT BULK COLLECT INTO statement, they are ized and extended automatically Recall that typically a nested table must be initialized prior to itsuse by calling a constructor function that has the same name as its nested table type After it hasbeen initialized, it must be extended using the EXTEND method before the next value can be

initial-assigned to it

To display this data, the collections are looped through using a numeric FOR loop Note how lower and upper limits for the loop counter are specified using the FIRST and LAST methods The BULK COLLECT clause is similar to a cursor loop in that it does not raise a NO_DATA_ FOUND exception when the SELECT statement does not return any records As a result, it is considered a good practice to check if a resulting collection contains any data.

Because the BULK COLLECT clause does not restrict the size of a collection and extends it matically, it is also a good idea to limit the result set when a SELECT statement returns large

auto-LAB 18.2

The BULK COLLECT Clause

423

amounts of data This can be achieved by using BULK COLLECT with a cursor SELECT and by adding the LIMIT option.

Define collection type and variables to be used by the

BULK COLLECT clause

TYPE student_id_type IS TABLE OF student.student_id%TYPE;

TYPE first_name_type IS TABLE OF student.first_name%TYPE;

TYPE last_name_type IS TABLE OF student.last_name%TYPE;

DBMS_OUTPUT.PUT_LINE ('student_id: '||student_id_tab(i));

DBMS_OUTPUT.PUT_LINE ('first_name: '||first_name_tab(i));

DBMS_OUTPUT.PUT_LINE ('last_name: '||last_name_tab(i));

LAB 18.2

424

The BULK COLLECT Clause

that in this case, the loop’s exit condition is based on the number of records in the collection rather than the student_cur%NOTFOUNDattribute.

Note how the numeric FOR loop that displays information on the screen has been moved inside the cursor loop This is done because every new batch of 50 records fetched by the BULK COLLECT replaces the previous batch of 50 records fetched in the previous iteration.

So far you have seen examples of the BULK COLLECT clause fetching data into collections where the underlying elements are simple data types such as NUMBER or VARCHAR2 However, the BULK COLLECT clause can be used to fetch data into collections of records or objects Collections of objects are discussed in Chapter 23, “Object Types in Oracle.” Consider

a modified version of the previous example, in which student data is fetched into a collection of user-defined records:

Define record type

TYPE student_rec IS RECORD

(student_id student.student_id%TYPE,first_name student.first_name%TYPE,last_name student.last_name%TYPE);

Define collection type

TYPE student_type IS TABLE OF student_rec;

Define collection variable

DBMS_OUTPUT.PUT_LINE('student_id: '||student_tab(i).student_id);

DBMS_OUTPUT.PUT_LINE('first_name: '|| student_tab(i).first_name);

LAB 18.2

The BULK COLLECT Clause

425

FOR EXAMPLE(continued)

DBMS_OUTPUT.PUT_LINE('last_name: '|| student_tab(i).last_name);

Define collection types and variables

TYPE row_num_type IS TABLE OF NUMBER INDEX BY PLS_INTEGER;

TYPE row_text_type IS TABLE OF VARCHAR2(10) INDEX BY PLS_INTEGER;

row_num_tab row_num_type;

row_text_tab row_text_type;

BEGIN

DELETE FROM TEST

RETURNING row_num, row_text

BULK COLLECT INTO row_num_tab, row_text_tab;

DBMS_OUTPUT.PUT_LINE ('Deleted '||SQL%ROWCOUNT ||' rows:');

state-row_text_tab, which are displayed on the screen.

When run, this script produces the following output:

row_num = 3 row_text = row 3

row_num = 4 row_text = row 4

row_num = 6 row_text = row 6

row_num = 8 row_text = row 8

row_num = 9 row_text = row 9

row_num = 10 row_text = row 10

PL/SQL procedure successfully completed

Throughout this chapter you have seen how to use the FORALL statement and BULK COLLECT clause Next, consider an example that combines both This example is based on the script ch18_1a.sql, which selects some data from the ZIPCODE table and inserts it into the MY_ZIPCODE table Changes are shown in bold.

FOR EXAMPLE

DECLARE

Declare collection types

TYPE string_type IS TABLE OF VARCHAR2(100) INDEX BY PLS_INTEGER;

TYPE date_type IS TABLE OF DATE INDEX BY PLS_INTEGER;

Declare collection variables to be used by the FORALL statement

BULK COLLECT INTO zip_tab, city_tab, state_tab, cr_by_tab,

cr_date_tab, mod_by_tab, mod_date_tab FROM zipcode

VALUES(zip_tab(i), city_tab(i), state_tab(i), cr_by_tab(i),cr_date_tab(i), mod_by_tab(i), mod_date_tab(i));

COMMIT;

LAB 18.2

The BULK COLLECT Clause

427

FOR EXAMPLE(continued)

Check how many records were added to MY_ZIPCODE table

18.2.1 Use the BULK COLLECT Statement

In this exercise, you create various scripts that select and modify data in the MY_INSTRUCTOR table inbulk

Create the MY_INSTRUCTOR table as follows If this table already exists, drop it and then re-create it

CREATE TABLE my_instructor AS

SELECT *

FROM instructor;

Complete the following tasks:

A) Create the following script: Select the instructor ID, first name, and last name from the

MY_INSTRUCTOR table, and display them on the screen Note that the data should be fetched

SELECT instructor_id, first_name, last_nameBULK COLLECT INTO instructor_id_tab, first_name_tab,

last_name_tabFROM my_instructor;

FOR i IN instructor_id_tab.FIRST instructor_id_tab.LASTLOOP

DBMS_OUTPUT.PUT_LINE ('instructor_id: '||instructor_id_tab(i));DBMS_OUTPUT.PUT_LINE ('first_name: '||first_name_tab(i));

DBMS_OUTPUT.PUT_LINE ('last_name: '||last_name_tab(i));

END LOOP;

END;

The declaration portion of this script contains definitions of three collection types and variables.The executable portion of the script populates collection variables using the SELECT statementwith the BULK COLLECT clause Finally, it displays on the screen data stored in the collection

variables by looping through them

When run, this script produces the following output:

As mentioned previously, the BULK COLLECT clause is similar to the cursor loop in that it does notraise a NO_DATA_FOUND exception when the SELECT statement does not return any rows.

Consider deleting all the rows from the MY_INSTRUCTOR table and then executing this script

again In this case the output is as follows:

SQL> DELETE FROM my_instructor;

10 rows deleted.

SQL> SET SERVEROUTPUT ON;

SQL> DECLARE

2 Define collection types and variables to be used by the

3 BULK COLLECT clause

4 TYPE instructor_id_type IS TABLE OFmy_instructor.instructor_id%TYPE;

5 TYPE first_name_type IS TABLE OFmy_instructor.first_name%TYPE;

6 TYPE last_name_type IS TABLE OFmy_instructor.last_name%TYPE;

13 Fetch all instructor data at once via BULK COLLECT clause

14 SELECT instructor_id, first_name, last_name

15 BULK COLLECT INTO instructor_id_tab, first_name_tab,

COLLECT clause does not cause any errors To prevent this error from happening, you can modifythe script as follows Changes are shown in bold.

DBMS_OUTPUT.PUT_LINE ('instructor_id:

'||instructor_id_tab(i));

DBMS_OUTPUT.PUT_LINE ('first_name: '||first_name_tab(i));DBMS_OUTPUT.PUT_LINE ('last_name: '||last_name_tab(i));END LOOP;

SELECT instructor_id, first_name, last_name FROM my_instructor;

Define collection types and variables to be used by the BULK COLLECT clause

TYPE instructor_id_type IS TABLE OFmy_instructor.instructor_id%TYPE;

TYPE first_name_type IS TABLE OF my_instructor.first_name%TYPE;TYPE last_name_type IS TABLE OF my_instructor.last_name%TYPE;

FETCH instructor_cur BULK COLLECT INTO instructor_id_tab, first_name_tab, last_name_tab

LIMIT v_limit;

EXIT WHEN instructor_id_tab.COUNT = 0;

FOR i IN instructor_id_tab.FIRST instructor_id_tab.LASTLOOP

DBMS_OUTPUT.PUT_LINE ('instructor_id:

'||instructor_id_tab(i));

DBMS_OUTPUT.PUT_LINE ('first_name: '||first_name_tab(i));DBMS_OUTPUT.PUT_LINE ('last_name: '||last_name_tab(i));END LOOP;

collection variables contain no more than five records for each iteration of the cursor loop Finally,

to display all the results on the screen, you move the FOR loop inside the cursor FOR loop Thisversion of the script produces output identical to the first version of the script

C) Modify the newly created script as follows: Instead of fetching data from the MY_INSTRUCTORtable into individual collections, fetch it into a single collection

ANSWER:To accomplish this task, the new record type must be declared so that a single tion type can be based on this record type

collec-LAB 18.2

432

Lab 18.2 Exercises

This is shown next Changes are shown in bold.

ch18_2d.sql, version 4.0

SET SERVEROUTPUT ON;

DECLARE

CURSOR instructor_cur ISSELECT instructor_id, first_name, last_nameFROM my_instructor;

Define record type TYPE instructor_rec IS RECORD (instructor_id my_instructor.instructor_id%TYPE, first_name my_instructor.first_name%TYPE, last_name my_instructor.last_name%TYPE);

Define collection type and variable to be used by the BULK COLLECT clause

TYPE instructor_type IS TABLE OF instructor_rec;

FETCH instructor_curBULK COLLECT INTO instructor_tabLIMIT v_limit;

EXIT WHEN instructor_tab.COUNT = 0;

FOR i IN instructor_tab.FIRST instructor_tab.LASTLOOP

DBMS_OUTPUT.PUT_LINE ('instructor_id: '||instructor_tab(i).instructor_id);

DBMS_OUTPUT.PUT_LINE ('first_name: '||instructor_tab(i).first_name);

DBMS_OUTPUT.PUT_LINE ('last_name: '||instructor_tab(i).last_name);

END LOOP;

END LOOP;

CLOSE instructor_cur;

END;

In this version of the script, you declare a user-defined record type with three fields Next, you

declare a single collection type based on this record type Then you fetch the results of the cursorinto a collection of records that you then display on the screen

LAB 18.2

Lab 18.2 Exercises

433

Next, consider another version that also creates a collection of records In this version, the tion type is based on the row type record returned by the cursor:

collec - ch18_2e.sql, version 5.0

SET SERVEROUTPUT ON;

DECLARE

CURSOR instructor_cur ISSELECT instructor_id, first_name, last_nameFROM my_instructor;

Define collection type and variable to be used by the BULK COLLECT clause

TYPE instructor_type IS TABLE OF instructor_cur%ROWTYPE;

FETCH instructor_curBULK COLLECT INTO instructor_tabLIMIT v_limit;

EXIT WHEN instructor_tab.COUNT = 0;

FOR i IN instructor_tab.FIRST instructor_tab.LASTLOOP

DBMS_OUTPUT.PUT_LINE ('instructor_id: '||instructor_tab(i).instructor_id);

DBMS_OUTPUT.PUT_LINE ('first_name: '||instructor_tab(i).first_name);

DBMS_OUTPUT.PUT_LINE ('last_name: '||instructor_tab(i).last_name);

TYPE first_name_type IS TABLE OF my_instructor.first_name%TYPE;TYPE last_name_type IS TABLE OF my_instructor.last_name%TYPE;

DBMS_OUTPUT.PUT_LINE ('Deleted '||SQL%ROWCOUNT||' rows ');

IF instructor_id_tab.COUNT > 0 THENFOR i IN instructor_id_tab.FIRST instructor_id_tab.LASTLOOP

DBMS_OUTPUT.PUT_LINE('instructor_id: '||instructor_id_tab(i));

DBMS_OUTPUT.PUT_LINE ('first_name: '||first_name_tab(i));DBMS_OUTPUT.PUT_LINE ('last_name: '||last_name_tab(i));END LOOP;

▼ T R Y I T Y O U R S E L F

In this chapter, you’ve learned about bulk SQL—specifically, the FORALL statement and the BULK

COLLECT clause Here are some projects that will help you test the depth of your understanding

Before beginning these exercises, create the MY_SECTION table based on the SECTION table This tableshould be created empty

1) Create the following script: Populate the MY_SECTION table using the FORALL statement with theSAVE EXCEPTIONS clause After MY_SECTION is populated, display how many records were

inserted

2) Modify the script you just created In addition to displaying the total number of records inserted

in the MY_SECTION table, display how many records were inserted for each course Use the BULKCOLLECT statement to accomplish this step Note that you should delete all the rows from the

MY_SECTION table before executing this version of the script

3) Create the following script: Delete all the records from the MY_SECTION table, and display howmany records were deleted for each course Use BULK COLLECT with the RETURNING option

The projects in this section are meant to have you use all the skills you have acquired throughout thischapter The answers to these projects can be found in Appendix D and on this book’s companion Website Visit the Web site periodically to share and discuss your answers

Try it Yourself 437

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C H A P T E R 1 9 Procedures

C H A P T E R O B J E C T I V E S

In this chapter, you will learn about

Creating procedures

Passing parameters into and out of procedures

A ll the PL/SQL you have written up to this point has been anonymous blocks that were run as scripts and compiled by the database server at runtime Now you will begin using modular code Modular code is a way to build a program from distinct parts (modules), each of which performs a specific function or task toward the program’s final objective As soon as modular code is stored on the database server, it becomes a database object, or subprogram, that is available to other program units for repeated execution To save code to the database, the source code needs to be sent to the server so that it can be compiled into p-code and stored in the database This chapter and the next two describe this process This short chapter introduces stored procedures Chapter 20, “Functions,” covers the basics of stored functions Chapter 21, “Packages,” pulls together all this material.

In Lab 19.1, you will learn more about stored code and how to write the type of stored code known as procedures In Lab 19.2, you will learn about passing parameters into and out of procedures.

BENEFITS OF MODULAR CODE

A PL/SQL module is any complete logical unit of work The five types of PL/SQL modules are anonymous blocks that are run with a text script (this is the type you have used so far), procedures, functions, packages, and triggers.

Using modular code offers two main benefits: It is more reusable, and it is more manageable.

You create a procedure either in SQL*Plus or in one of the many tools for ing and debugging stored PL/SQL code If you are using SQL*Plus, you need to write your code in a text editor and then run it at the SQL*Plus prompt.

The last section of the module is an optional exception-handling section, which is where the code to handle exceptions is placed.

ANONYMOUS BLOCK

So far, you have only written anonymous blocks Anonymous blocks are much like modules, except that anonymous blocks do not have headers There are important differences, though As the name implies, anonymous blocks have no name and thus cannot be called by another block They are not stored in the database and must be compiled and then run each time the script is loaded.

The PL/SQL block in a subprogram is a named block that can accept parameters and that can

be invoked from an application that can communicate with the Oracle database server A subprogram can be compiled and stored in the database This allows the programmer to reuse the program It also allows for easier code maintenance Subprograms are either procedures or functions.

CHAPTER 19

440

Query the data dictionary for information on procedures

A procedure is a module that performs one or more actions; it does not need to return any values The syntax for creating a procedure is as follows:

CREATE OR REPLACE PROCEDURE name

A procedure may have zero to many parameters, as covered in Lab 19.2 Every procedure has three parts: the header portion, which comes before AS (sometimes you see IS; they are inter- changeable); the keyword, which contains the procedure name and parameter list; and the body, which is everything after the AS keyword The word REPLACE is optional When REPLACE is not used in the header of the procedure, to change the code in the procedure, you must drop and then re-create the procedure Because it is very common to change a procedure’s code, espe- cially when it is under development, it is strongly recommended that you use the OR REPLACE option.

L A B 1 9 1 E X E R C I S E S

This section provides exercises and suggested answers, with discussion related to how those answersresulted The most important thing to realize is whether your answer works You should figure out theimplications of the answers and what the effects are of any different answers you may come up with

ch19_01a.sql

CREATE OR REPLACE PROCEDURE Discount

AS

CURSOR c_group_discountIS

SELECT distinct s.course_no, c.descriptionFROM section s, enrollment e, course cWHERE s.section_id = e.section_idAND c.course_no = s.course_noGROUP BY s.course_no, c.description,

e.section_id, s.section_idHAVING COUNT(*) >=8;

BEGIN

FOR r_group_discount IN c_group_discountLOOP

UPDATE courseSET cost = cost * 95WHERE 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;

At a SQL*Plus session, run the previous script

Then answer the following questions:

A) What do you see on the screen? Explain what happens

ANSWER:The procedure is created The procedure named Discount is compiled into p-code andstored in the database for later execution If an error is generated, you must have made a typingmistake Check the code and recompile

B) Execute the Discount procedure How do you accomplish this? What results do you see on the

screen?

ANSWER:

SQL> EXECUTE Discount

5% discount has been given to 25 Adv Word Perfect

(through each course with an enrollment over 8)

PL/SQL procedure successfully completed

C) The script does not contain a COMMIT Discuss the issues involved with placing a COMMIT in theprocedure, and indicate where the COMMIT could be placed

ANSWER:Because this procedure does not have a COMMIT, the procedure will not update thedatabase A COMMIT needs to be issued after the procedure is run if you want the changes to bemade Alternatively, you can enter a COMMIT either before or after the end loop If you put theCOMMIT before the end loop, you are committing the changes after every loop If you put the

COMMIT after the end loop, the changes are not committed until the procedure is near tion It is wiser to use the second option This way, you are better prepared to handle errors

comple-LAB 19.1

442

Lab 19.1 Exercises

to see a portion of the code in order to isolate errors.

19.1.2 Query the Data Dictionary for Information on Procedures

Two main views in the data dictionary provide information on stored code USER_OBJECTS shows youinformation about the objects, and USER_SOURCE shows you the text of the source code The data

dictionary also has ALL_ and DBA_ versions of these views

Complete the following tasks:

A) Write a SELECT statement to get pertinent information from the USER_OBJECTS view about theDiscount procedure you just wrote Run the query and describe the results

ANSWER:

SELECT object_name, object_type, status

FROM user_objectsWHERE object_name = 'DISCOUNT';

The output is as follows:

OBJECT_NAME OBJECT_TYPE STATUS

-

-DISCOUNT PROCEDURE VALID

The status indicates that the procedure was compiled successfully An invalid procedure cannot

be executed

B) Write a SELECT statement to display the source code from the USER_SOURCE view for the

Discount procedure

ANSWER:

SQL> column text format a70

SELECT TO_CHAR(line, 99)||'>', textFROM user_source

WHERE name = 'DISCOUNT'

BY THE WAY

A procedure can become invalid if the table it is based on is deleted or changed You can recompile

an invalid procedure using this command:

alter procedure procedure_name compile

LAB 19.1

Lab 19.1 Exercises

443

L A B 1 9 2

Passing Parameters into and

out of Procedures

L A B O B J E C T I V E

After completing this lab, you will be able to

Use IN and OUT parameters with procedures

Parameters are the means to pass values to and from the calling environment to the server These are the values that are processed or returned by executing the procedure The three types of parameter modes are IN, OUT, and IN OUT.

MODES

Modes specify whether the parameter passed is read in or a receptacle for what comes out.

Figure 19.1 illustrates the relationship between parameters when they are in the procedure header versus when the procedure is executed.

LAB 19.2

444

EXECUTE FIND_NAME (127, NAME)

PROCEDURE FIND_NAME (ID IN NUMBER, NAME OUT VARCHAR2)

PROCEDURE HEADER:

PROCEDURE CALL:

FIGURE 19.1

Matching a procedure call to a procedure header

FORMAL AND ACTUAL PARAMETERS

Formal parameters are the names specified in parentheses as part of a module’s header Actual parameters are the values or expressions specified in parentheses as a parameter list when the

module is called The formal parameter and the related actual parameter must be of the same or compatible datatypes Table 19.1 explains the three types of parameters.

TABLE 19.1

Three Types of Parameters

IN Passes a value into the program Read-only value

Constants, literals, expressionsCannot be changed within the program’s default modeOUT Passes a value back from the program Write-only value

Cannot assign default valuesMust be a variable

A value is assigned only if the program is successful

IN OUT Passes values in and also sends values back Has to be a variable

PASSING CONSTRAINTS (DATATYPE) WITH PARAMETER VALUES

Formal parameters do not require constraints in the datatype For example, instead of ing a constraint such as VARCHAR2(60), you just say VARCHAR2 against the parameter name

specify-in the formal parameter list The constraspecify-int is passed with the value when a call is made.

MATCHING ACTUAL AND FORMAL PARAMETERS

You can use two methods to match actual and formal parameters: positional notation and named notation Positional notation is simply association by position: The order of the parameters used when executing the procedure matches the order in the procedure’s header Named notation is explicit association using the symbol =>:

19.2.1 Use IN and OUT Parameters with Procedures

Create the following text file in a text editor Run the script at a SQL*Plus session

o_first_name OUT VARCHAR2,o_last_name OUT VARCHAR2)

AS

BEGIN

SELECT first_name, last_nameINTO o_first_name, o_last_nameFROM student

WHERE student_id = i_student_id;

EXCEPTION

WHEN OTHERSTHEN

DBMS_OUTPUT.PUT_LINE('Error in finding student_id:

'||i_student_id);

END find_sname;

A) Explain what happens in the find_snameprocedure What parameters are passed into and out

of the procedure? How would you call the procedure? Call the find_snamescript with the

following anonymous block:

DBMS_OUTPUT.PUT_LINE('Student 145 is: '||v_local_first_name||

' '|| v_local_last_name||'.');

END;

ANSWER:The procedure takes in a student_idusing the parameter named

i_student_id It passes out the parameters o_first_nameando_last_name

The procedure is a simple select statement that retrieves the first_nameandlast_namefrom the Student table, where the student_idmatches the value of i_student_id

i_student_idis the only in parameter that exists in the procedure To call the procedure, avalue must be passed in for the i_student_idparameter

B) Explain the relationship between the parameters that are in the procedure’s header definition

versus the parameters that are passed into and out of the procedure

ANSWER:When calling the procedure find_sname, a valid student_idshould be passed

in for i_student_id If it is not a valid student_id, an exception is raised Two variablesmust also be listed when calling the procedure These variables,v_local_first_nameandv_local_last_name, are used to hold the values of the parameters that are being passedout After the procedure has been executed, the local variables have a value and can then be

displayed with a DBMS_OUTPUT.PUT_LINE

LAB 19.2

446

Lab 19.2 Exercises