The MarcXchange standard, currently at stage 90.20, is undergoing review by TC 46 SC 4. Developed by the US Library of Congress in 2001, MarcXchange is an XML-based framework designed for handling MARC (Machine-Readable Cataloging) data in an XML environment.
Key features of MarcXchange include its MARCXML schema, enabling lossless round-trip conversion of ISO 2709 MARC 21 records and XML-encoded MARC 21 records. It serves as a generalized version of MARCXML with minimal changes, tightly coupled to ISO 2709, and functions as an XML extension to ISO 2709.
The standard facilitates the conversion of records using ISO 2709 syntax into XML and acts as a framework for this purpose. Extensions to MarcXchange may be necessary for retaining the definition and application of fields, subfields, and control characters specific to ISO 2709 implementations.
MarcXchange addresses the international exchange of records, accommodating local variations by serving as a framework for creating local schemas or incorporating local extensions, ensuring compatibility. It recognizes the need for local deviations, even when local formats such as MARC 21 or UNIMARC are chosen.
In terms of its relationship to MARC and ISO 2709:
- The XML schema of MarcXchange contains MARC data.
- It can be used for the exchange of MARC records or function as a "bus" for further transformations, such as conversion to Dublin Core or validation processes.
- Specific handling is applied to components of ISO 2709 (e.g., record label, directory, record identifier field, control fields, data fields, subfields) in the MarcXchange schema during the conversion process.
Overall, MarcXchange provides a standardized and versatile framework for working with MARC data in an XML environment, facilitating interoperability and compatibility in the international exchange of bibliographic records.