FRBR Hierarchy¶
The core of the MerMEId MeLODy data model follows the FRBR (Functional Requirements for Bibliographic Records) hierarchy, as formalised in LRMoo. This hierarchy separates a musical work into four conceptually distinct levels.
Work
└── Expression (a specific realisation of the work)
└── Manifestation (a published or distributed version of the expression)
└── Item (a single physical or digital copy)
Understanding this hierarchy is fundamental to working with MerMEId MeLODy, because it determines how entities relate to one another and which fields are appropriate at each level.
Work¶
Class: melod:Work
Folder: works/
A Work represents the abstract intellectual or artistic creation — the composer's intention, independent of any particular realisation, notation, or performance. A single work may give rise to many different expressions.
Example: Beethoven's Symphony No. 9 in D minor, Op. 125 is a Work. It exists as an abstract concept, identified by the composer's intention and the thematic catalogue entry — not tied to any specific score or recording.
Fields:
- Title (primary and alternative titles)
- Composer (linked Person as Contributor with role as Composer)
- Catalogue numbers (opus number, thematic catalogue reference such as BWV, TWV, etc.)
- Historic context of the work creation
- Genre and sub-genre as classifications
- Evidence as linked bibliography
- Related works (part of a larger collection, preceded by, derived from, etc.)
- Is realised in (linked Expression)
Expression¶
Class: melod:Expression
Folder: expressions/
An Expression is a specific realisation of a Work or a Source — a distinct version defined by its musical content: instrumentation, arrangement, language, number of movements, and so on. The same abstract Work can have multiple Expressions.
Example: An arrangement of Beethoven's 9th for piano solo is a different Expression from the full orchestral score. A revision by the composer that adds a new movement creates another Expression.
Fields:
- Label of this realisation
- Scoring/instrumentation (linked Instrumentation entity)
- Movements and sections (can reference other Expressions as components)
- Key, Meter, Tempo, mensuration and extent
- Duration of the performed expression
- Musical incipits (in PAE — Plaine and Easie Code — format or linked MEI)
- Performance events (linked PerformanceEvents)
- Related expressions (arrangements, translations, revisions)
- Completion status
Manifestation¶
Class: melod:Manifestation
Folder: manifestations/
A Manifestation is a published or otherwise distributed embodiment of an Expression — an edition, print run, manuscript type, or digital publication. All copies produced from the same printing or distribution constitute one Manifestation.
Example: The first edition of the score published by Breitkopf & Härtel in 1826 is a Manifestation. A later critical edition by another publisher is a separate Manifestation of the same Expression.
Fields:
- Title as it appears on the manifestation and link to identifier (RISM)
- Publisher and place/date of publication
- Physical description (dimensions, watermark, plate number, inscriptions) and formatted title pages (for manifestation singletons)
- Classifications
- Related manifestations (reprints, facsimile editions)
- Embodies (Linked Expression)
Item¶
Class: melod:Item
Folder: items/
An Item is a single physical or digital copy of a Manifestation — a specific exemplar held at a particular institution or location. Two copies of the same printed edition are two different Items.
Example: The copy of the 1826 Breitkopf & Härtel score held at the Staatsbibliothek Berlin, with shelfmark Mus.ms. 1234, is one Item.
Fields:
- Label and link to identifier (RISM)
- Holding institution/repository (linked Institution)
- Shelfmark and former shelfmark
- Provenance notes as events and date of acquisition
- Physical description (dimensions, watermark, plate number, inscriptions, condition) and formatted title pages
- Scribes (linked Persons and Medium description)
- Link to digitisation (if available)
- Classifications
- Related items (components)
- Materialization Of (Linked Manifestation)
How the Levels Relate¶
In practice, not every catalogue entry requires all four levels. A thematic catalogue might focus primarily on Works and Expressions, using Items only when documenting specific sources. The editor does not enforce a strict hierarchy — you can create an Item without a parent Manifestation, for example — but the relational fields in each form are designed to connect the levels.
Links between levels are stored as RDF property references between entity IRIs, for example: