1. 09/15/981 XML: Basics Paul V. Biron Permanente Clinical Systems Development Kaiser Permanente, Southern California Paul.V.Biron@kp.org

2. 09/15/982 Outline HTML, SGML and XML –The World Wide Web Consortium (W3C) –HTML as an application of SGML –XML: define your own tag set –XML vs. "standard" HL7 encoding Document Type Definitions (DTDs) Well-formed vs. valid Elements Attributes Entities

3. 09/15/983 Outline (cont.) The "XML Family" of Standards XSL XLL Namespaces Next generation schema definition languge Benefits to be gained Representational expansion Wide availability of toolsets Wide availability of trained personnel

4. 09/15/984 HTML, SGML, XML HTML: HyperText Markup Language – Recommendation of the World Wide Web Consortium (W3C) –an application of SGML (the HTML DTD) SGML: Standard Generalized Markup Language –ISO 8879:1986(E) XML is a proper subset of SGML –XML and SGML are metalanguages Language for defining other languages Recommendation of the W3C –Formally Adopted on 10-February-1998

5. 09/15/985 Patient Information Name: Henry Levin, the 7th MRN: 123456789 DOB: May 13, 1923 Clinical Data History of smoking for 40 years. Procedure Chest X-ray Findings Comparison is made with a chest-x-ray … Impressions RLL nodule, suggestive of malignancy. Compared with a prior CXR from 6 months ago, nodule size has increased. Recommendations I notified the ordering physician of this finding by phone. Radiology Report - Chest X-Ray Patient Information Name: Henry Levin, the 7th MRN: 123456789 DOB: May 13, 1923 Clinical Data History of smoking for 40 years. Procedure Chest X-Ray Findings Comparison is made with a chest x-ray... Impressions RLL nodule, suggestive of malignancy. Compared with a prior CXR from 6 months ago, nodule size has increased. Recommendations I notified the ordering physician of this finding by phone. HTML is SGML (although not XML)

6. 09/15/986 Henry Levin, the 7th 123456789 May 13, 1923 History of smoking for 40 years. Chest X-ray Comparison is made with a chest-x-ray … RLL nodule, suggestive of malignancy. Compared with a prior CXR from 6 months ago, nodule size has increased. I notified the ordering physician of this finding by phone. Radiology Report - Chest X-Ray Patient Information Name: Henry Levin, the 7th MRN: 123456789 DOB: May 13, 1923 Clinical Data History of smoking for 40 years. Procedure Chest X-Ray Findings Comparison is made with a chest x-ray... Impressions RLL nodule, suggestive of malignancy. Compared with a prior CXR from 6 months ago, nodule size has increased. Recommendations I notified the ordering physician of this finding by phone. XML - Define your own tags

7. 09/15/987 Henry Levin, the 7th 123456789 May 13, 1923 History of smoking for 40 years. Chest X-ray Comparison is made with a chest-x-ray … RLL nodule, suggestive of malignancy. Compared with a prior CXR from 6 months ago, nodule size has increased. I notified the ordering physician of this finding by phone. <!ELEMENT RadiologyReport (PatientInfo, ClinicalData, Procedure, Findings, Impressions, Recommendations)> <!ELEMENT PatientInfo (Name, MRN, DOB)> XML - Define your tag arrangement

8. 09/15/988 Henry Levin, the 7th 123456789 May 13, 1923 History of smoking for 40 years. Chest X-ray Comparison is made with a chest-x-ray … RLL nodule, suggestive of malignancy. Compared with a prior CXR from 6 months ago, nodule size has increased. I notified the ordering physician of this finding by phone. MSH… PID|1||123456789||Levin^Henry^^the 7th||19230513 OBR|1|||^Chest X-ray OBX|1|TX|71020&GDT||Clinical data: History of smoking for 40 years. OBX|2|TX|71020&GDT||Findings: Comparison is made with a chest-x- ray … OBX|3|CE|71020&IMP||^RLL nodule, suggestive of malignancy. Compared with a prior CXR from 6 months ago, nodule size has increased. OBX|4|CE|71020&REC||^I notified the ordering physician of this finding by phone. XML vs. Standard Encoding HL7 Message

9. 09/15/989 … MSH… PID|1||123456789||Levin^Henry^^the 7th||19230513 OBR|1|||^Chest X-ray OBX|1|TX|71020&GDT||Clinical data: History of... OBX|2|TX|71020&GDT||Findings: Comparison is made … OBX|3|CE|71020&IMP||^RLL nodule, suggestive of... OBX|4|CE|71020&REC||^I notified the ordering physician... XML vs. Standard Encoding HL7 Message

10. 09/15/9810 Document Type Definitions –also referred to as DTDs Provide a "schema" for a class of documents –A "schema" defines certain semantic and structural constraints, including A set of element declarations Documentation Optional supporting specifications, such as style sheets –DTDs are one language for writing schemas for both SGML and XML documents Recent proposals (e.g., Document Content Descriptors, submission to W3C) have been made

11. 09/15/9811 prolog element Misc* XML Document A well-formed document must match the production labeled document In common usage, this often translates to: The elements, delimited by start- and end-tags, nest properly within each other An XML document is valid if it has an associated document type declaration and if the document complies with the constraints expressed in it Well-Formed vs. Valid

12. 09/15/9812 Overview of XML

13. 09/15/9813 Elements …... XML Document Element Only other elements may be present in the elements content You can control the order of these sub-elements

14. 09/15/9814 Attributes … <!ATTLIST OBX.3 CE.1 CDATA #IMPLIED CE.2 CDATA #IMPLIED CE.3 CDATA #IMPLIED>... XML Document String (CDATA) String (or CDATA) attributes may take any literal string as a value, including whitespace characters CDATA (character data)

15. 09/15/9815 Entities prolog element XML Document General and Parameter Entity Definitions Parameter Entity References General Entity References

16. 09/15/9816 The "XML Family" of Standards XSL: Extensible Style Language –Declarative language for "screen rendering" and transformation –Will allow a single XML file to be "rendered" in multiple formats viewing HL7 messages in a standard web browser –W3C V1.0 "working draft" released August 18, 1998 XLL: Extensible Link Language –Inter/Intra document linking specifications –HTML's on steroids –Xlink W3C working draft released March 3, 1998 –Xpointer W3C working draft released March 3, 1998

17. 09/15/9817 The "XML Family" of Standards Namespaces –Mechanism for avoiding element/attribute name collisions –W3C working draft released August 2, 1998 To be incorporated into a future revision of the XML Specification Next generation "schema" definition languages –DTD's on steroids More extensive datatyping Inheritance mechanism(s) –W3C working group recently formed –Working draft(s)/recommendation(s) at least 1 year away "Document Content Description" W3C submission acknowledged August 10, 1998

18. 09/15/9818 The Benefits to be Gained Representational expansion –Recursive (segment-less) encodings –"self-documenting" structures Wide availability of toolsets –XML parsers and parser SDKs –Stylesheet editors and processors –Transformation (conversion) engines Wide availability of trained personnel –XML programmers

19. 09/15/9819 prolog element XML Document Questions