Bridging two biomedical journal databases with XML - a case study

For transferring data between heterogeneous databases, XML is becoming a method of choice. While deployment is generally successful, there are barriers to overcome. A recent example at the National Library of Medicine (NLM) involved transfers between “DCMS” (Data Creation and Maintenance System) and “Mars” (Medical Article Records System). These two document workflow systems, with separate databases, process biomedical journals for incorporation into NLM´s “MEDLINE”bibliographic database. DCMS acts as an overall manager, while Mars is one of three decoupled methods for harvesting the abstracts and citation information from articles. A pre-existing flow of article information from the “back-end” of Mars was first recast into XML for delivery to DCMS by an “upload” daemon. Next addressed was the lack of data flow from DCMS to the Mars “front-end”, necessitating duplicative data entry by Mars operators. The desired flow was achieved as XML, mediated by a new “CheckIn” module. Bumps hit on the road to successful deployment of these transfer applications are discussed