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MARC Authority Record Data Structure Design

Status: ✅ COMPLETED

This design has been fully implemented. Authority records (Type Z) and Holdings records are now fully supported with readers, writers, and comprehensive test coverage. See epic mrrc-fzy for implementation details (4 subtasks completed 2025-12-21 through 2025-12-26).

Overview

MARC Authority records (Type Z, Leader/06='z') are used to maintain standardized forms of names, subjects, and titles. They differ fundamentally from bibliographic records:

  • Bibliographic records describe items/resources
  • Authority records describe headings and their variants

Core Differences from Bibliographic Records

Aspect Bibliographic Authority
Leader/06 a, c, d, e, g, i, j, k, m, o, p, r, t z
Main entry 245 (Title) 1XX (Heading)
Variants 4XX, 5XX are optional fields 4XX (See), 5XX (See Also) are primary content
Purpose Describe a resource Establish normalized headings and cross-references
Scope Broader range of data Focused on names, subjects, titles

Authority Record Heading Types (1XX field)

The 1XX field defines the type of authority record:

  • 100 - Personal names (X00 pattern)
  • 110 - Corporate names (X10 pattern)
  • 111 - Meeting names (X11 pattern)
  • 130 - Uniform titles (X30 pattern)
  • 148 - Chronological terms (X48 pattern)
  • 150 - Topical terms (X50 pattern)
  • 151 - Geographic names (X51 pattern)
  • 155 - Genre/form terms (X55 pattern)

Key Fields and Content

Control Fields (00X-09X)

Same basic structure as bibliographic records: - 001 - Control Number - 005 - Date and Time of Latest Transaction - 008 - Fixed-length data elements (authority-specific)

008 Authority-Specific Positions

Position Name Values
00-05 Date entered on file yymmdd
06 Direct/indirect geographic subdivision a, i, n,
07 Type of URI a, b, c, d, (fill)
08 Undefined (fill)
09 Kind of record a, b, c, d, e, f, g
10 Descriptive cataloging rules a, b, c, (fill)
11 Subject heading system/thesaurus a, b, c, d, k, n, v, z, (fill)
12 Type of series a, b, c, (fill)
13 Number series/dates of birth-death a, b, (fill)
14 Heading use-main or added entry a, b
15 Heading use-subject added entry a, b
16 Heading use-series added entry a, b
17 Type of subject subdivision n, p, (fill)
28 Type of government agency a, b, c, d, u, z, (fill)
29 Reference evaluation a, b, c, d, n, (fill)
31 Record update in process a, b
32 Undifferentiated personal name a, b, n
33 Level of establishment a, b, c, d, n
34 Modified record (space), d
35 Source of heading or term a, c, (fill)
39 Cataloging source (space), c

Heading Fields (1XX)

Single, primary heading field containing the established form.

Structure: Same as bibliographic field structure (indicators + subfields)

Examples: 

100 1_ $aSmith, John,$d1873-1944.$tAutobiography
110 2_ $aNEW YORK (STATE).$bDepartment of Environmental Conservation
150 _0 $aArtistic anatomy

Tracing and Reference Fields (4XX, 5XX)

Track variant and related headings.

4XX - See From Tracing Fields

Show variants NOT used as headings (point TO the 1XX): - 400 - See From Tracing-Personal Name - 410 - See From Tracing-Corporate Name - 411 - See From Tracing-Meeting Name - 430 - See From Tracing-Uniform Title - 448 - See From Tracing-Chronological Term - 450 - See From Tracing-Topical Term - 451 - See From Tracing-Geographic Name - 455 - See From Tracing-Genre/Form Term

5XX - See Also From Tracing Fields

Show related headings that ARE authorized (point BETWEEN headings): - 500 - See Also From Tracing-Personal Name - 510 - See Also From Tracing-Corporate Name - 511 - See Also From Tracing-Meeting Name - 530 - See Also From Tracing-Uniform Title - 548 - See Also From Tracing-Chronological Term - 550 - See Also From Tracing-Topical Term - 551 - See Also From Tracing-Geographic Name - 555 - See Also From Tracing-Genre/Form Term

Note Fields (6XX, 66X, 67X, 68X)

Provide context and history: - 667 - Nonpublic General Note - 670 - Source data found (used for verification) - 671 - Source data not found (negative reference) - 680 - Public General Note - 681 - Subject heading or term note - 685 - History note

Relationship/Linking Fields (7XX)

Link to other authorized headings: - 700 - Established Heading Linking Entry-Personal Name - 710 - Established Heading Linking Entry-Corporate Name - 711 - Established Heading Linking Entry-Meeting Name - 730 - Established Heading Linking Entry-Uniform Title - 748 - Established Heading Linking Entry-Chronological Term - 750 - Established Heading Linking Entry-Topical Term - 751 - Established Heading Linking Entry-Geographic Name - 755 - Established Heading Linking Entry-Genre/Form Term

Proposed Rust Data Structures

AuthorityRecord Structure

pub struct AuthorityRecord {
    pub leader: Leader,
    pub control_fields: BTreeMap<String, String>,
    pub heading: Option<Field>,          // 1XX field
    pub tracings_see_from: Vec<Field>,   // 4XX fields
    pub tracings_see_also: Vec<Field>,   // 5XX fields
    pub notes: Vec<Field>,               // 66X, 67X, 68X fields
    pub linking_entries: Vec<Field>,     // 7XX fields
    pub other_fields: BTreeMap<String, Vec<Field>>, // Other data fields
}

AuthorityRecordBuilder

Similar to RecordBuilder, provide fluent API for constructing authority records:

pub struct AuthorityRecordBuilder {
    record: AuthorityRecord,
}

impl AuthorityRecordBuilder {
    pub fn heading(mut self, field: Field) -> Self { ... }
    pub fn add_see_from(mut self, field: Field) -> Self { ... }
    pub fn add_see_also(mut self, field: Field) -> Self { ... }
    pub fn add_note(mut self, field: Field) -> Self { ... }
    pub fn build(self) -> AuthorityRecord { ... }
}

Helper Methods on AuthorityRecord

impl AuthorityRecord {
    // Get the 1XX heading
    pub fn heading(&self) -> Option<&Field> { ... }

    // Get heading type (PersonalName, CorporateName, etc.)
    pub fn heading_type(&self) -> Option<HeadingType> { ... }

    // Get all 4XX see-from tracings
    pub fn see_from_tracings(&self) -> Vec<&Field> { ... }

    // Get all 5XX see-also tracings
    pub fn see_also_tracings(&self) -> Vec<&Field> { ... }

    // Get notes
    pub fn notes(&self) -> Vec<&Field> { ... }

    // Get source data notes (670)
    pub fn source_data_found(&self) -> Vec<&Field> { ... }

    // Check if heading is fully established
    pub fn is_established(&self) -> bool { ... }

    // Get kind of record from 008/09
    pub fn kind_of_record(&self) -> Option<KindOfRecord> { ... }
}

Enums for Authority-Specific Values

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum HeadingType {
    PersonalName,
    CorporateName,
    MeetingName,
    UniformTitle,
    ChronologicalTerm,
    TopicalTerm,
    GeographicName,
    GenreFormTerm,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum KindOfRecord {
    EstablishedHeading,
    ReferenceUntracted,
    ReferenceTraced,
    Subdivision,
    EstablishedHeadingAndSubdivision,
    ReferenceAndSubdivision,
    NodeLabel,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum LevelOfEstablishment {
    FullyEstablished,
    Memorandum,
    Provisional,
    Preliminary,
    NotApplicable,
}

Implementation Phases - COMPLETED

  1. Phase 1 (mrrc-fzy.1): Design and define data structures ✅
  2. ✅ Create AuthorityRecord struct with unified BTreeMap field storage
  3. ✅ Implement enums for authority-specific values (HeadingType, KindOfRecord, LevelOfEstablishment)
  4. ✅ Create helper methods for common operations

  5. ✅ Add unit tests for structure validation

  6. Phase 2 (mrrc-fzy.2): Reader/Writer ✅

  7. ✅ Extended reader to detect and parse authority records
  8. ✅ Implemented authority record writer

  9. ✅ Roundtrip serialization tested

  10. Phase 3 (mrrc-fzy.3): Holdings records design ✅

  11. ✅ Designed HoldingsRecord data structures

  12. ✅ Implemented comprehensive unit tests

  13. Phase 4 (mrrc-fzy.4): Holdings reader/writer ✅

  14. ✅ Implemented holdings record reader
  15. ✅ Implemented holdings record writer
  16. ✅ Comprehensive roundtrip testing

Key Considerations

  1. Reuse existing structures: Authority records use same Leader, Field, Subfield types as bibliographic records
  2. Focused structure: AuthorityRecord doesn't need all the methods bibliographic records have (no publication info, no ISBN validation needed)
  3. Field organization: Clear separation of heading, tracings, notes, and linking fields
  4. Validation: Ensure 1XX is present, proper field relationships
  5. Type safety: Use enums to encode authority-specific concepts from 008 field