WHAT IS THE DIFFERENCE BETWEEN PROCEDURE AND FUNCTION?

PROCEDURE FUNCTION

Procedure is mainly used to perform one or more specific task.Function is mainly used to compute a value.

Procedure can not be called from the sql statements .Function can be called from the sql statements.

A Procedure may or may not return a value using the OUT parameters.A Function must return a value.

The RETURN statement of procedure returns control to the calling program and cannot return a value.The RETURN statement of function returns control to the calling program and return the result of the function.

Procedure are not considered as expression.Functions are considered as expressions.

HOW WILL YOU CREATE PAKAGES IN PL/SQL.GIVE EXAMPLE THAT ADDS ONE FUNCTION AND ONE PROCEDURE IN PAKAGES?PACKAGE SPECIFICATIONThe package specification is required when you create a new package.The package specification lists all the objects which are publicly accessible from other applications. It declares the types,variables,constants,exceptions,cursors.and subprograms.The scope of these declarations is local to your database schema and global to the package.so,the declared objects are accessible from your application and from anywhere in the package .To create a package or package specification,use the CREATE PACKAGE statement ,which you execute interactivelyfrom sql*plus. Here is the syntax:CREATE [OR REPLACE] PACKAGE package_name {is | as}Procedure_specification;Function_specification;Variable_declaration;Type_defination;Exception_declaration;Cursor_declaration;END [package_name];

PACKAGE BODYA package body contains the code that implements the package specification. It fully defines cursors,procedures and functions declared in the package specification.Unlike a package specification, the declarative part of a package body can contain subprogram bodies.To create a package body, use the CREATE PACKAGE BODY statement, which you can execute interactively from sql*Plus.here is the syntax:CREATE [OR REPLACE] PACKAGE BODY package_name {IS|AS}Procedure_defination;Function_definition;Private_variable_declaration;Private_type_defination;Cursor_defination;[BEGINExecutable_statements;[EXCEPTIONexception_handlers]]END [package_name];The following steps are followed to develop a package:1. First create the package specification using CREATE PACKAGE statement. Then we compile the source. The source code is compiled into P Code.2. Then the package body is created using CREATE PACKAGE BODY statement within SQL script file. Then we compile this code and check for error if any.3. After creating the package specification and its body, you reference the objects declared in the package specification from outside the package specification using dot notation.