Brief History of ADL Metadata Schema
Alexandria Digital Library: Metadata
A Brief History of the Alexandria Digital Library Metadata Schema
When designing the schema for Alexandria's metadata, two standards were followed. Both were important for representing spatial metadata. The first standard was the USMARC, a national standard for libraries since the 1960s. The second standard was the Federal Geographic Data Committee (FGDC) Standard. This federally mandated standard was in use since early 1995, with the expressed intent of sharing a standard set of geospatial metadata. These two standards reached agreement such that FGDC fields which did not exist in USMARC were added to USMARC.
Neither standard alone fully represented both digital spatial data and analog materials. As a result, both FGDC and USMARC were merged into the Alexandria schema. During the original design of the schema, Alexandria used the USMARC local-use fields to create additional fields for analog spatial data not found in either standard.
Issues relating to the use of a Relational Database Management System (RDBMS), into which the schema was implemented, affecting the Alexandria schema are the set-oriented retrieval of a query which must completely finish before showing any results and the need for multiple joins of repeated tables -- both slowing search/retrieval time. The schema currently has 455 attributes in 81 tables.
Contact :: metadata@alexandria.sdc.ucsb.edu
Last modified on 1997-01-24 at 17:10 GMT by the Alexandria Web Team