When integrating complex enterprise systems, transformation patterns allow for flexibility in how messages are handled in the system. With transformation, a message between two applications can be altered and/or enhanced. Here are some transformation-related patterns:

• Content Enricher: A message is enriched by adding information.
• Canonical Data Model: A message is transformed into an application-neutral message format.
• Message Translator: A pattern for translating one message to another.

The Canonical Data Model (CDM) is a good pattern to highlight. With this pattern, a message can be exchanged between multiple applications without having to perform a translation for each specific message type. This is best shown by an example of multiple systems exchanging messages, as illustrated in the following diagram:

In the diagram, applications A and C want to send their messages in their format to application B and D. If we used the Message Translator pattern, only the process, which is handling the transformation, would need to know how to translate from A to B and from A to D as well as C to B and C to D. This becomes increasingly difficult as the number of applications increases and when the publisher might not know the details of its consumers. With the CDM, source application messages for A and B are translated into a neutral schema X.

The message in the neutral schema format is then translated to the message formats for B and D as shown in the following diagram:

In the enterprise, this becomes unmanageable without some standards, and fortunately, many organizations have been created to produce as well as govern standards in many industries, including the following examples (but there are many more!):

• Electronic Data Interchange For Administration, Commerce and Transport (EDIFACT): An international standard for trade
• IMS Question and Test Interoperability specification (QTI): Standards for the representation of assessment content and results produced by the Information Management System (IMS) Global Learning Consortium (GLC)
• Hospitality Industry Technology Integration Standards (HITIS): Standards for property management systems maintained by the American Hotel and Motel Association
• X12 EDI (X12): Collection of schemas for health care, insurance, government, finance, transportation, and other industries maintained by the Accredited Standards Committee X12
• Business Process Framework (eTOM): Telecommunications operating model maintained by the TM Forum