PL/SQL Package

In PL/SQL, a package is a schema object that groups logically related PL/SQL types, variables, constants, subprograms, cursors, and exceptions.

It provides a way to encapsulate and organize code for easier maintenance and reuse.

Packages offer several benefits, including encapsulation, information hiding, modularity, and improved performance due to reduced parsing overhead.

They are widely used in PL/SQL development for building modular and maintainable applications.

CREATE OR REPLACE PACKAGE package_name AS

  -- Declarations of types, constants, variables, cursors, exceptions, etc.

  -- These declarations are visible to the outside world (public).

 

  PROCEDURE procedure_name(param1 IN datatype1, param2 OUT datatype2);

  FUNCTION function_name(param IN datatype) RETURN datatype;

 

END package_name;

/

CREATE OR REPLACE PACKAGE BODY package_name AS

  -- Definitions of procedures, functions, and other executable code.

  -- These definitions are hidden from the outside world (private).

 

  PROCEDURE procedure_name(param1 IN datatype1, param2 OUT datatype2) IS

  BEGIN

    -- Implementation of the procedure

  END procedure_name;

 

  FUNCTION function_name(param IN datatype) RETURN datatype IS

  BEGIN

    -- Implementation of the function

  END function_name;

 

END package_name;

/

We create a package named rectangle_pkg.

Inside the package specification, we declare a constant pi and two procedures calculate_area and calculate_perimeter.

These are visible to the outside world.

calculate_area procedure calculates the area of a rectangle given its length and width.

calculate_perimeter procedure calculates the perimeter of a rectangle given its length and width.

In the package body, we define the implementation of the procedures.

Both procedures take input parameters length and width and return the calculated area or perimeter through the OUT parameter.

The package encapsulates the logic related to rectangle calculations, providing a modular and reusable solution.