MARC - Overview

Overview of MARC Structure

Original Lecture Video

Structure of MARC

• Structure – Form that the information takes in a computer record (Order of elements; lengths of fields; how fields are subdivided)
• MARC and EAD require an order of elements, unlike DACS

Composition of MARC record

• Record structure – adheres to the ANSI standard for bibliographic information interchange (ANSI Z39.2)
• Content designation – codes and conventions used to characterize the data, which is established by MARC
• Content of the data elements – governed by a content standard (e.g. DACS)

MARC Tags and Codes

• Field tag – three character numeric codes which identify fields of information (e.g. 100, 245, 300)
• Indicators – one character codes which come immediately after field tags and provide information on the content of the tag; not always used
• Subfield codes – define elements within a field; are preceded by a character called a delimiter sign (often the characters $ or # are used)

Major components of MARC record in bibliographic format

• Leader and Directory – fixed; 24 characters long; often supplied automatically (no data entry required)
• Variable fields – Control fields (no indicators or subfield; 00X fields); Data fields (two indicator positions, two-character subfield codes preceding each data element within the field)

Other important aspects of MARC record structure

• Field/subfield repeatability – some fields and subfields are repeatable and some are not (e.g. each record may only have one 1XX, or main entry); commonly repeatable fields include 300, 6XX, and 7XX; check the MARC format online to see which can be repeated, R is repeatable and NR is not
• Display constants – some systems are programmed to display certain descriptive information automatically, so you don't have to type in things like “scope and content” every time you input this information; these constants are often controlled by indicator codes – kind of like turning it on or off, depending on what code you put in; Check the MARC format codes online to make sure you have it when you want it or don't

Major blocks of fields for MARC

0XX – control information, numbers, codes

1XX – Main entry

2XX – titles, edition, imprint

3XX – physical description, etc

4XX – series statements (but this is different than archival series)

5XX – Notes (used a lot)

6XX – subject access fields

7XX – Name, etc added entries or series, linking

8XX – series added entries, holdings and locations

9XX – reserved for local implementation