IBM Data Management magazine Issue 2, 2009

e includes IBM WebSphere MQ for asynchronous messaging and queuing. For HL7 messaging, the UCLA Health System uses Sun SeeBeyond eGate Integrator which, according to Dr. Wang, is “the enterprise-wide standard for all application interfaces.”

The PODS queue manager operates with an input queue, xception queue, and replication queue. The standard services for managing metadata and image files provide application programming interfaces (APIs) for uploading, downloading, querying, and updating documents. The system supports auditing by generating a report of all activity against the database except uploads.

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The evolution of PODS

The UCLA Health System PODS implementation supports access to patient documentation with DB2 pureXML capabilities for loading, querying, and updating data. It provides a set of Web services interfaces that enable clinical systems to upload and query data.

The most recent versions of the system are PODS3 and ODS4. Both were built on an SOA, but use different DB2

capabilities for XML processing. For XML messaging in the form of SOAP-based Web services, PODS3 and PODS4 use a combination of Systinet and IBM WebSphere software.

However, the PODS4 implementation marked a transi-on from the DB2 XML Extender to the pureXML capabilities of DB2 9. For example, DB2 9 introduced support for a feature defined by the SQL:2003 standard, an XML column type treated as a first-class data type. You can use the XML type in Data Definition Language (DDL) statements, functions, and stored procedures.

Another benefit of the move to DB2 9 is the hybrid torage engine and a query optimizer that “understands” XML (mapping to relational algebra for queries involving XML). The migration to PODS4 did not change the PODS functional requirements, but pureXML processing simplified metadata processing while meeting the system’s response time and scalability goals.

The upload process illustrates the difference between ODS3 and PODS4. When there was an upload of a PDF

document, for example, the PODS3 upload process stored the document and an XML metadata file on the EMC file server. It decomposed the metadata for use by the DB2 SQL storage engine as an XCollection, a type implemented by the DB2 XML Extender. The upload also validated the schema using the IBM WebSphere Application Server parser and indexed the path to the PDF and XML files in the DB2 database. The DB2 transaction associated with an upload included generating a unique document ID, logging the upload in the activity

history table, and executing a SQL INSER T into 18 tables.

The PODS4 upload process treats the XML document metadata differently. Instead of storing metadata across 18 tables, the PODS4 upload process saves it using DB2 columns of type XML and does an INSERT query into four tables.

Simplified processing and standards compliance

Moving from PODS3 to PODS4 with DB2 9 greatly simplified the UCLA Health System’s database administration and replication tasks. The PODS3 architecture used DB2 8 with the XML Extender, and a database consisting of 28 tables. The PODS4 database design, using XML columns, required only 10 tables and eliminated 20 stored procedures used by PODS3.

Because the UCLA Health System uses XML for patient metadata, supporting a new electronic form in the PODS collection involves creating the data definition or schema for form content. DBAs dealing with a constant stream of new forms want efficient solutions for defining new types of data, such as test results. Moving to DB2 9 reduced the amount of time required to add new forms and schemas to the system: supporting a new form in PODS4 typically takes two hours, compared with two weeks in PODS3.

In any industry, standards are essential for interoper-bility and efficient data interchange. XML has become a powerful tool for healthcare providers in part because it offers an effective tool for markup and for defining vocabularies for data interchange and archiving. However, robust applications require a reliable data management infrastructure. PODS illustrates how one healthcare provider is addressing the challenge of creating, storing, and exchanging electronic medical records. With PODS, UCLA Health System—like other healthcare institutions— has embraced XML technology and started down a path that leads to sophisticated electronic medical records, compliance with HIPAA guidelines and HL7 standards, and increased productivity.

Ken North is a consultant, author, industry analyst, and editor of www.SQLSummit.com. He teaches Expert Series seminars and has chaired the XML DevCon 200x conference series, LinkedData Planet, and DataServices World conferences.