Procedure and Functions
Procedures Syntax:
[CREATE [OR REPLACE]] PROCEDURE
[(p1, p2…)] [IS | AS]
[declarations]
BEGIN
[Execution Statements]
[EXCEPTIONS
exception_handling]
END [Pname];
/
Pname
2
Example
CREATE
PROCEDURE
PrintName
IS
Address
VARCHAR2(50);
BEGIN
Address := ‘102 Main St, Frostburg MD 21532’;
DBMS_OUTPUT.PUT_LINE(Address);
END PrintName;
/
3
Run the Procedure
 EXEC
 EXEC
PrintName();
PrintName;
4
Procedure with Parameter
CREATE OR REPLACE PROCEDURE Print_B_Date (V_ID NUMBER)
IS
V_B_Date
DATE;
BEGIN
SELECT B_Date INTO
V_B_Date
FROM Employee
WHERE ID=V_ID;
DBMS_OUTPUT.PUT_LINE(V_B_Date);
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE(‘No Data Found’);
END Print_B_Date;
/
5
Call Procedure & Check for Errors
 EXEC Print_B_Date(112);
 SHOW ERRORS;
6
Example
CREATE PROCEDURE Largest (P1 NUMBER, P2 NUMBER)
IS
BEGIN
DBMS_OUTPUT.PUT_LINE(‘The First Number is’ || P1);
DBMS_OUTPUT.PUT_LINE(‘The Second Number is’ || P2);
IF(P1>P2) THEN
DBMS_OUTPUT.PUT_LINE(‘The Largest Number is’ || P1);
ELSE
DBMS_OUTPUT.PUT_LINE(‘The Largest Number is’ || P2);
END IF;
END Largest;
/
7
Call Procedure
 EXEC
Largest(12, 24);
 EXEC Largest(24, 12);
8
Procedure with default value
CREATE PROCEDURE Data ( Name VARCHAR2,
B_Date DATE DEFAULT SYSDATE)
IS
BEGIN
DBMS_OUTPUT.PUT_LINE(Name || B_Date);
END;
/
9
Procedure Call
 EXEC Data(‘Jim Smith’, ‘12-MAR-03’)
 EXEC Data(‘Mary Show’);
10
Dropping Procedure
 DROP
PROCEDURE
Largest;
11
Functions Syntax:
[CREATE [OR REPLACE]] FUNCTION
[(p1, p2…)] RETURN datatype [IS | AS]
[declarations]
BEGIN
[Execution Statements]
[EXCEPTIONS
exception_handling]
END [Fname];
/
Fname
12
Example
CREATE FUNCTION PrintNameF RETURN
BOOLEAN
IS
Address
VARCHAR2(50);
BEGIN
Address := ‘102 Main St, Frostburg MD 21532’;
DBMS_OUTPUT.PUT_LINE(Address);
RETURN true;
END PrintNameF;
/
13
Run a Function:
DECLARE
flag
BOOLEAN;
BEGIN
Flag:=PrintNameF;
IF flag THEN
DBMS_OUTPUT.PUT_LINE(‘Function Printed Correctly’));
END IF;
END;
/
14
Function with Parameter
CREATE OR REPLACE FUNCTION Print_B_DateF (V_ID NUMBER) RETURN CHAR
IS
V_B_Date
DATE;
found
CHAR(1):=‘F’;
F_ID
NUMBER:=V_ID;
BEGIN
SELECT
B_Date
INTO
V_B_Date
FROM
Employee
WHERE
ID=F_ID;
DBMS_OUTPUT.PUT_LINE(V_B_Date);
found:=‘T’;
RETURN found;
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE(‘No Data Found’);
END Print_B_DateF;
/
15
Calling a Function:
SELECT
FROM
Print_B_DateF(102)
DUAL;
16
Dropping Function
DROP
FUNCTION Print_B_DateF;
17
Find the largest Value
DECLARE –--p1, p2, p3, p4
large
NUMBER;
BEGIN
large:=p1;
IF large< p2 THEN large:=p2; END IF;
IF large< p3 THEN large:=p3; END IF;
IF large< p4 THEN large:=p4; END IF;
END;
/
18
PACKAGES
 DBMS_OUTPUT.NEW_LINE;
 DBMS_OUTPUT.PUT_LINE ('Display This’);
19
PACKAGE HEADER
(Specification)
CREATE [ OR REPLACE] PACKAGE p_name IS |AS
-- functions
-- procedures
-- variables
-- constants
-- exceptions
-- cursors
END [p_name ];
20
EXAMPLE
CREATE PACKAGE myPackage AS
PROCEDURE PrintLarge (P1 NUMBER, p2 NUMBER);
FUNCTION FindLarge (P1 NUMBER, P2 NUMBER) RETURN
NUMBER;
END myPackage;
21
PACKAGE BODY
CREATE OR REPLACE PACKAGE BODY p_name IS|AS
--package body
End p_name;
22
EXAMPLE
CREATE OR REPLACE PACKAGE BODY MyPackage AS
PROCEDURE PrintLarge (P1 NUMBER, p2 NUMBER) AS
BEGIN IF p1> p2 THEN
DBMS_OUTPUT.PUT_LINE(p1);
ELSE
DBMS_OUTPUT.PUT_LINE(p2);
END IF;
END PrintLarge;
FUNCTION FindLarge (P1 NUMBER, P2 NUMBER) RETURN NUMBER AS
large NUMBER;
BEGIN IF p1> p2 THEN
LARGE:=p1;
ELSE
LARGE:=p2;
END IF;
RETURN LARGE;
END ;
END myPackage;
23
Call Elements of Package:
EXEC MyPackage.PrintLarge (32 , 11);
SELECT
FROM
MyPackage.FindLarge( 22 , 43)
DUAL;
24
EXAMPLE 2
CREATE OR REPLACE PACKAGE Employee_p AS
FUNCTION E_Full_Name (Last_N testdata.employee.L_name%TYPE,
First_N testdata.employee.F_name%TYPE) RETURN
VARCHAR2;
FUNCTION E_Name(E_id testdata.employee.id%TYPE) RETURN
VARCHAR2;
END Employee_p;
25
EXAMPLE 2
CREATE OR REPLACE PACKAGE BODY Employee_P AS
FUNCTION E_Full_Name
(Last_N Employee.L_name%TYPE,
First_N Employee.F_name%TYPE)
RETURN VARCHAR2 IS
BEGIN
RETURN Last_N || ‘, ‘ || First_N;
END;
26
EXAMPLE 2
FUNCTION E_Name(f_id EMPLOYEE.id%TYPE) RETURN
VARCHAR2 IS
temp
VARCHAR2(200);
id
EMPLOYEE.id%TYPE:=f_id;
BEGIN
SELECT
(L_name || ‘ ‘ ||F_Name) INTO temp
FROM
employee
WHERE
employee.id = id;
RETURN temp;
EXCEPTION
WHEN NO_DATA_FOUND THEN
RETURN NULL;
WHEN TOO_MANY_ROWS THEN
…..
END;
27
CALL FUNCTIONS of PACKAGE
SELECT
FROM
Employee_p.E_NAME(107)
DUAL;
28
Subprogram Location
 USER_OBJECTS
 USER_SOURCE
 USER_ERRORS
SELECT
FROM
WHERE
OBJECT_NAME, OBJECT_TYPE, STATUS
USER_OBJECTS
OBJECT_NAME = ‘PrintInfo’;
OBJECT_NAME
OBJECT_TYPE
STATUS
SIMPLE
PROCEDURE
VALID
29
Subprogram Location
SELECT
FROM
WHERE
TEXT
USER_SOURCE
NAME = ‘PrintInfo’ AND TYPE= ‘PROCEDURE’
ORDER BY line;
TEXT
----------------------------------------CREATE OR REPLACE PROCEDURE PrintInfo AS
ss NUMBER:=24;
BEGIN
DBMS_OUTPUT.PUT_LINE(ss);
END PrintInfo;
30
Find Errors:
SHOW ERRORS;
-Line number of the error
-Column number of the error
-Text message of the error
SELECT
FROM
WHERE
line, position, text
USER_ERRORS
name=‘PrintInfo’ AND
TYPE=‘PROCEDURE’;
31
Exception Handling
CREATE FUNCTION Employee_P (f_id EMPLOYEE.id%TYPE) RETURN
VARCHAR2 IS
temp
VARCHAR2(200);
id
EMPLOYEE.id%TYPE:=f_id;
BEGIN
SELECT
(L_name || ‘ ‘ ||F_Name) INTO temp
FROM
employee
WHERE
employee.id = id;
RETURN temp;
EXCEPTION
WHEN NO_DATA_FOUND THEN
RETURN NULL;
WHEN TOO_MANY_ROWS THEN
INSERT INTO errors
VALUES (‘Error in statement ‘);
RETURN NULL;
END Employee_P;
32
Exception Handling
DECLARE
BEGIN
EXCEPTION
WHEN ZERO_DIVIDE THEN
INSERT INTO table1(info)
VALUES (info_data);
COMMIT;
WHEN OTHERS THEN
ROLLBACK;
END;
33
Exception Types:
1.
Predefined Oracle Server errors:
No declaration is needed
ORA-01403
NO_DATA_FOUND
ORA-01422
TOO_MANY_ROWS
ORA-01476
ZERO_DIVIDE
ORA-06500
STORAGE_ERROR
ORA-06530
ACCESS_INTO_NULL
ORA-06592
CASE_NOT_FOUND
ORA-00001
DUP_VAL_ON_INDEX

34
Exception Types:
2.
User_defined


User determines an abnormal condition
Declared in declaration section
DECLARE
e_TooManyNumbers EXCEPTION;
35
Raising USER_DEFINED Exceptions
 Example
DECLARE
e_TooManyNumbers EXCEPTION;
V_NoStudent
NUMBER(4);
V_MaxStudent
NUMBER(4);
BEGIN
SELECT
Current_Students, Max_Students
INTO
V_NoStudent, V_MaxStudent
FROM
classes
WHERE
C_Num=455 AND Dept=‘ITEC’;
IF V_NoStudent > V_MaxStudent THEN
RAISE e_TooManyNumbers;
END IF;
36
EXCEPTION
WHEN e_TooManyNumbers THEN
INSERT INTO log_file (info)
VALUES (‘ITEC455 has:‘ || V_NoStudent || ‘Max No is:’ ||
V_MaxStudent);
END;
Chapter 18: Exception Handling
37