Implementations of routines

Routines can be implemented in a variety of ways. A routine implementation is essentially the underlying form of the routine that contains the logic that is run when a routine is invoked. Understanding the different supported routine implementations can help you understand how routines work and help you determine which routine implementation to choose when implementing user-defined routines.

The available routine implementations include:

Built-in routines can be implemented as built-in routines, SQL routines, or external routines. However, their implementation is essentially invisible to the user and in general is of little concern to the user.

User-defined routines can be implemented as sourced routines, SQL routines, or external routines.

The characteristics of each of the implementations differ and can result in more or less functionality support. Before deciding on a particular implementation, it is a good idea to review the supported functionality and restrictions associated with each implementation, by reading about each of the implementations and then by reading the topic:

A good understanding of the routine implementations can help you make good implementation decisions as well as help you to debug and troubleshoot existing routines.