Database Packages

In Oracle, packages encapsulate related procedures, functions, and associated cursors and variables together as a unit in the database. Packages usually have two parts, a specification and a body. The specification is the interface with your applications; it declares the types, variables, constants, exceptions, cursors, and subprograms available for use. The body fully defines cursors and subprograms, and so implements the specification.

Packages provide advantages in the following areas:

Encapsulation of related procedures and variables in a single named, stored unit in the database. This provides for better organization during the development process and makes privilege management easier.
Separation of public and private procedures, variables, constants, and cursors.
Better performance since entire package is loaded into memory when an object from the package is called for the first time.

Creating a Database Package
You create a database package as follows:
Inserting Procedures in a Database Package
A database package is a set of related procedures. When you create a database package, you have to declare the procedures it contains.
Database Package Procedures
A package procedure is created in a database package. If you delete the database package you also delete the procedures it contains.
Database Package Variables
Variables can be declared within a package. A variable can be used in a SQL or PL/SQL statement to capture or provide a value when one is needed.
Database Package Cursors
A cursor is a multi-row query, which lets you name a work area and access its stored information.
Database Package Exceptions
PL/SQL allows you to explicitly handle internal and user-defined error conditions, called exceptions, that arise during processing of PL/SQL code.
Database Package Types
A type is a user-defined composite datatype that encapsulates a data structure along with the functions and procedures needed to manipulate the data. You can also define subtypes of object types: a subtype contains all the attributes and methods of the parent type, it can contain additional attributes and can override methods from the type.
Database Package Parameters
Database package procedures and cursors can use input and output parameters.
Rebuilding Database Package Procedures
You can rebuild database package procedure dependencies (along with other procedure dependencies) by selecting Tools Rebuild Objects Rebuild Procedures Dependencies .
Generating Database Packages
You can define generation parameters for database packages in the Database Package tab of the Triggers and Procedures Generation dialog box.
Reverse Engineering Database Packages
You can select database packages to reverse engineer from the Database Package tab of the Database Reverse Engineering dialog box.

Parent topic: Oracle