PL/SQL PL/SQL SubprogramsSubprograms

PL/SQL PL/SQL SubprogramsSubprograms

Session - IVSession - IVSession - IVSession - IV

What are SubPrograms?.What are SubPrograms?.

Subprograms are named PL/SQL block that can take parameters and be invoked.

Two Types of Subprogram.

PROCEDURESFUNCTIONS

Where are They Allowed?Where are They Allowed?

Subprograms can be defined using any ORACLE tool that supports PL/SQL

Must be declared at the end of a declarative section after all other program objects.

E.g.:-E.g.:-

Declare

PROCEDURE TEST IS

DBMS_OUTPUT.PUT_LINE(‘Testing’);

End;

Begin

Test;

End;

ProcedureProcedure

Is Subprogram that performs a specific action.

Has two parts the specification and body.

Specification begins with the keyword PROCEDURE and end with Procedure Name.

Parameter Declaration are

optional.

Procedure body begins with the keyword END followed by an optional Procedure Name.

The Procedure body has 3 Parts

Declarative PartExecutable partOptional Exception-Part

Declarative Part Contains Local Declarations which are placed between IS and BEGIN.

Declare

Procedure Pn is

enam varchar(15);

BeginSelect ename INTO enam from emp where

empno=7369;

DBMS_OUTPUT.PUT_LINE(ENAM);

End;

Parameter ModesParameter ModesParameter ModesParameter Modes

INOUT IN OUT

ININININ

Lets you pass value to the subprogram being called.

OUTOUTOUTOUT

Lets you pass return values to the caller of a Subprogram

IN OUTIN OUTIN OUTIN OUT

Lets you pass initial values to the subprogram and return updated values to the caller.

FunctionFunctionFunctionFunction

A Function is a Subprogram that computes a value. Functions and Procedures are structured alike, Except that functions have a RETURN clause.

FunctionFunctionFunctionFunctionCREATE OR REPLACE FUNCTION FUN (ID

NUMBER)

RETURN CHAR IS

NAME EMP.ENAME%TYPE;

BEGIN

SELECT ENAME INTO NAME FROM EMP WHERE EMPNO=ID;

RETURN(NAME);

END;

CREATE OR REPLACE FUNCTION FUN (ID NUMBER)

RETURN CHAR IS

NAME EMP.ENAME%TYPE;

BEGIN

SELECT ENAME INTO NAME FROM EMP WHERE EMPNO=ID;

RETURN(NAME);

END;

CREATE OR REPLACE FUNCTION F1(N NUMBER) RETURN NUMBERISSALARY EMP.SAL%TYPE;BEGINSELECT SAL INTO SALARY FROM EMP WHERE EMPNO=N;RETURN SALARY;END;

DECLAREA number(30);BEGINA:=F1(&N);DBMS_OUTPUT.PUT_LINE(A);END;

( OR )

SELECT F1(7369) from dual;

PACKAGESPACKAGESPACKAGESPACKAGES

Is an encapsulated collection of related program objects stored together in the database.

Is an encapsulated collection of related program objects stored together in the database.

Program Objects are :-Program Objects are :-Program Objects are :-Program Objects are :-ProceduresProceduresFunctionsFunctionsVariablesVariablesConstantsConstantsCursorsCursorsExceptionsExceptions

ProceduresProceduresFunctionsFunctionsVariablesVariablesConstantsConstantsCursorsCursorsExceptionsExceptions

CREATE PACKAGESCREATE PACKAGESCREATE PACKAGESCREATE PACKAGES

There are Two Distinct Steps to Create Package

1. PACKAGE SPECIFICATION

2. PACKAGE BODY

There are Two Distinct Steps to Create Package

1. PACKAGE SPECIFICATION

2. PACKAGE BODY

PACKAGE SPECIFICATIONPACKAGE SPECIFICATIONPACKAGE SPECIFICATIONPACKAGE SPECIFICATION

CREATE PACKAGE Command

<> can declare Program Objects

i.e.. Procedures ,Functions etc..

CREATE PACKAGE Command

<> can declare Program Objects

i.e.. Procedures ,Functions etc..

PACKAGE BODYPACKAGE BODYPACKAGE BODYPACKAGE BODY

CREATE PACKAGE BODY Command

can declare and define Program Objects

CREATE PACKAGE BODY Command

can declare and define Program Objects

CREATE OR REPLACE PACKAGE P56 ISPROCEDURE P4(ENO NUMBER);END;

CREATE OR REPLACE PACKAGE P56 ISPROCEDURE P4(ENO NUMBER);END;

CREATE OR REPLACE PACKAGE BODYCREATE OR REPLACE PACKAGE BODY P56 ISP56 ISPROCEDURE P4(ENO NUMBER) ISPROCEDURE P4(ENO NUMBER) ISDESG EMP.JOB%TYPE; DESG EMP.JOB%TYPE; BEGINBEGINSELECT JOB INTO DESG FROM EMP SELECT JOB INTO DESG FROM EMP WHERE EMPNO=ENO;WHERE EMPNO=ENO;DBMS_OUTPUT.PUT_LINE(DESG);DBMS_OUTPUT.PUT_LINE(DESG);END P4;END P4;

END P56;END P56;

CREATE OR REPLACE PACKAGE BODYCREATE OR REPLACE PACKAGE BODY P56 ISP56 ISPROCEDURE P4(ENO NUMBER) ISPROCEDURE P4(ENO NUMBER) ISDESG EMP.JOB%TYPE; DESG EMP.JOB%TYPE; BEGINBEGINSELECT JOB INTO DESG FROM EMP SELECT JOB INTO DESG FROM EMP WHERE EMPNO=ENO;WHERE EMPNO=ENO;DBMS_OUTPUT.PUT_LINE(DESG);DBMS_OUTPUT.PUT_LINE(DESG);END P4;END P4;

END P56;END P56;