OVERVIEW

This tutorial demonstrates how to model HL7 data by using DFDL schema.

HL7 Version 2.x defines a series of electronic messages to support clinical, administrative, logistical and financial processes. Since 1987 the standard has been updated regularly, resulting in the latest version 2.7 which is backward compatible with earlier 2.x versions. HL7 Version 2 messages use a non-XML text syntax based on segments (usually separated by carriage-return) and one-character delimiters.

Segments contain fields separated by the field delimiter. A field can have components separated by the component delimiter, and a component can have sub-components separated by the sub-component delimiter. The default delimiters are pipe (|) for the field separator, caret (^) for the component separator, and ampersand (&) for the sub-component separator. The tilde (~) is the default repetition separator for fields that repeat. Each segment starts with a 3-character initiator which identifies the segment type. Fields, components and sub-components do not have initiators.

Every message starts with a special MSH segment, which includes a field that identifies the message type. The message type determines the expected segment types in the message. The MSH also defines the delimiters that are used by the message. Each segment of the message contains one specific category of information. Healthcare organizations are able to extend the standard by providing their own segments with 3-character initiators starting with 'Z'.

The DFDL schema editor is used to view the model and parse example HL7 message files.