SQL Navigator for Oracle 7.4 - Installation Notes

A procedure is a sequence of executable statements that performs a particular action. Procedures can be stored in the database (where they are also executed) and reused; they are then referred to as stored procedures. Stored procedures cannot be embedded in a SQL statement.

A function is a block that returns a value. Functions can be stored in the database and reused. Stored functions can be called from within a SQL statement.

A package is an encapsulated collection of related schema objects, including modules and other constructs, such as cursors, variables, exceptions, and records. Packages allow procedures, functions, variables, and cursors that share common or related functions to be compiled and stored as a single schema object.

• Packages allow encapsulation of internal subroutines and variables.
• With packages, you can specify which code is publicly available to programmers and which data should be hidden. In addition, you can implement global variables, data structures, and values; these persist for the duration of a user session.
• Packages have both a specification and a body. The package specification declares procedures, functions, cursors, and variables.
• The package body contains the implementation of the public procedures and functions, together with internal and private programs and variables.

Object types are user-defined data types, equivalent to "classes" in object-oriented languages, that may consist of composite data types or collections such as repeating groups or complex record types. Object types may be associated with member functions and procedures that are implemented in PL/SQL. These modules implement the methods of the object type.

Like packages, object types have both a specification and a body.

• The specification lists the object's attributes and member functions.
• The body contains the actual code for the methods.