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Show transfer at the level of all data for a specific hospital admission. The ARZAP process removes sets of data from the virtual files to accommodate incoming data. The sets of data to be removed from the files are determined by the VAM process. The ARZAP process receives messages from the VAM process that specify the sets of data that are to be deleted. ARZAP then removes the specified data from the files so that the file space can be reclaimed. The virtual database also supports different access paths. In the production version of this virtual database the set of supported access paths will be the same as the set of paths that are supported by the HELP database. In this way, users can sequentially scan through the archive of patients based on any one of the available orderings of patients. For the prototype only two paths were supported: alphabetical access based on patient name, and sequential access based on the primary key. In order to support transparent access of the virtual database for users of the HELP database-access primitives, two key primitives (IDDATA, RETRIEVE) were modified to recognize the virtual database. These two primitives were programmed to detect when the virtual database is being accessed and to communicate with the virtual database manager in the event that requested data are not found in the database. 3.4 The Size of the Virtual Database Files The database of the HELP System is oriented toward single-patient care. Thus, the HELP database-access routines reflect this orientation. The HELP database-access routines are designed to access data for a particular hospital admission. This 30 |
