The entities that have been defined for this study represent the key objects of interest to users of bibliographic data. The entities have been divided into three groups. The first group comprises the products of intellectual or artistic endeavour that are named or described in bibliographic records: work, expression, manifestation, and item. The second group comprises those entities responsible for the intellectual or artistic content, the physical production and dissemination, or the custodianship of such products: person and corporate body. The third group comprises an additional set of entities that serve as the subjects of intellectual or artistic endeavour: concept, object, event, and place.
Sections 3.1.1 through 3.1.3 present the entities in each of the three groups in a simplified schematic form, depicting the underlying relationships between each of the entity types.
Sections 3.2.1 through 3.2.10 provide a more detailed explanation of each of the entities defined in the model.
Chapter 5 (sections 5.2.1 through 5.2.3) provides a more detailed explanation of the relationships between the different types of entities that are depicted in the entity-relationship diagrams in sections 3.1.1. through 3.1.3.
The entities in the first group (as depicted in Figure 3.1) represent the different aspects of user interests in the products of intellectual or artistic endeavour. The entities defined as work (a distinct intellectual or artistic creation) and expression (the intellectual or artistic realization of a work) reflect intellectual or artistic content. The entities defined as manifestation (the physical embodiment of an expression of a work) and item (a single exemplar of a manifestation), on the other hand, reflect physical form.
The relationships depicted in the diagram indicate that a work may be realized through one or more than one expression (hence the double arrow on the line that links work to expression). An expression, on the other hand, is the realization of one and only one work (hence the single arrow on the reverse direction of that line linking expression to work). An expression may be embodied in one or more than one manifestation; likewise a manifestation may embody one or more than one expression. A manifestation, in turn, may be exemplified by one or more than one item; but an item may exemplify one and only one manifestation.
The entities in the second group (outlined in bold in Figure 3.2) represent those responsible for the intellectual or artistic content, the physical production and dissemination, or the custodianship of the entities in the first group. The entities in the second group include person (an individual) and corporate body (an organization or group of individuals and/or organizations).
The diagram depicts the type of "responsibility" relationships that exist between entities in the second group and the entities in the first group. The diagram indicates that a work may be created by one or more than one person and/or one or more than one corporate body. Conversely, a person or a corporate body may create one or more than one work. An expression may be realized by one or more than one person and/or corporate body; and a person or corporate body may realize one or more than one expression. A manifestation may be produced by one or more than one person or corporate body; a person or corporate body may produce one or more than one manifestation. An item may be owned by one or more than one person and/or corporate body; a person or corporate body may own one or more than one item.
The entities in the third group (outlined in bold in Figure 3.3) represent an additional set of entities that serve as the subjects of works. The group includes concept (an abstract notion or idea), object (a material thing), event (an action or occurrence), and place (a location).
The diagram depicts the "subject" relationships between entities in the third group and the work entity in the first group. The diagram indicates that a work may have as its subject one or more than one concept, object, event, and/or place.
Conversely, a concept, object, event, and/or place may be the subject of one or more than one work.The diagram also depicts the "subject" relationships between work and the entities in the first and second groups. The diagram indicates that a work may have as its subject one or more than one work, expression, manifestation, item, person, and/or corporate body.
The first entity defined in the model is work: a distinct intellectual or artistic creation.
A work is an abstract entity; there is no single material object one can point to as the work. We recognize the work through individual realizations or expressions of the work, but the work itself exists only in the commonality of content between and among the various expressions of the work. When we speak of Homer's Iliad as a work, our point of reference is not a particular recitation or text of the work, but the intellectual creation that lies behind all the various expressions of the work.
Because the notion of a work is abstract, it is difficult to define precise boundaries for the entity. The concept of what constitutes a work and where the line of demarcation lies between one work and another may in fact be viewed differently from one culture to another. Consequently the bibliographic conventions established by various cultures or national groups may differ in terms of the criteria they use for determining the boundaries between one work and another.
For the purposes of this study variant texts incorporating revisions or updates to an earlier text are viewed simply as expressions of the same work (i.e., the variant texts are not viewed as separate works). Similarly, abridgements or enlargements of an existing text, or the addition of parts or an accompaniment to a musical composition are considered to be different expressions of the same work. Translations from one language to another, musical transcriptions and arrangements, and dubbed or subtitled versions of a film are also considered simply as different expressions of the same original work.
By contrast, when the modification of a work involves a significant degree of independent intellectual or artistic effort, the result is viewed, for the purpose of this study, as a new work. Thus paraphrases, rewritings, adaptations for children, parodies, musical variations on a theme and free transcriptions of a musical composition are considered to represent new works. Similarly, adaptations of a work from one literary or art form to another (e.g., dramatizations, adaptations from one medium of the graphic arts to another, etc.) are considered to represent new works. Abstracts, digests and summaries are also considered to represent new works.
On a pragmatic level, defining work as an entity in the model serves a number of purposes. It enables us to give a name and draw relationships to the abstract intellectual or artistic creation that encompasses all the individual expressions of that work. Thus, when we describe a work of literary criticism dealing with Homer's Iliad, for example, we are able to relate the work of criticism to the work that it treats as its subject. By naming Homer's work and defining the relationship between it and the work of criticism, we are able to indicate that the subject of the work of criticism is in fact the abstraction we know as the Iliad, and not any specific expression of that work.
Defining work as an entity also enables us to establish indirect relationships between expressions of the same work in cases where we are unable to draw direct relationships between individual expressions. For example, there may exist many translations of a work (e.g., Anne of Green Gables), and it may not always be possible or necessary to specify the text that has served as the basis for a given translation. In that case we do not draw a direct relationship between individual expressions of the work (i.e., between the translation and the text or texts on which the translation was based), but we relate those and other texts and translations of the work implicitly by relating each of them to the entity we call the work.
Relating expressions of a work indirectly by relating each expression to the work that it realizes is often the most efficient means of grouping related expressions. In effect, the name we give to the work serves as the name for the entire set or group of expressions that are realizations of the same intellectual or artistic creation (e.g., Lancelot du Lac). It is the entity defined as work, therefore, that provides us with this grouping capability.
The second entity defined in the model is expression: the intellectual or artistic realization of a work in the form of alpha-numeric, musical, or choreographic notation, sound, image, object, movement, etc., or any combination of such forms.
An expression is the specific intellectual or artistic form that a work takes each time it is "realized." Expression encompasses, for example, the specific words, sentences, paragraphs, etc. that result from the realization of a work in the form of a text, or the particular sounds, phrasing, etc. resulting from the realization of a musical work. The boundaries of the entity expression are defined, however, so as to exclude aspects of physical form, such as typeface and page layout, that are not integral to the intellectual or artistic realization of the work as such. When an expression is accompanied by augmentations, such as illustrations, notes, glosses, etc. that are not integral to the intellectual or artistic realization of the work, such augmentations are considered to be separate expressions of their own separate work(s). Such augmentations may, or may not, be considered significant enough to warrant distinct bibliographic identification.
Inasmuch as the form of expression is an inherent characteristic of the expression, any change in form (e.g., from alpha-numeric notation to spoken word) results in a new expression. Similarly, changes in the intellectual conventions or instruments that are employed to express a work (e.g., translation from one language to another) result in the production of a new expression. If a text is revised or modified, the resulting expression is considered to be a new expression. Minor changes, such as corrections of spelling and punctuation, etc., may be considered as variations within the same expression.
Defining expression as an entity in the model gives us a means of reflecting the distinctions in intellectual or artistic content that may exist between one realization and another of the same work. With expression defined as an entity, we can describe the intellectual or artistic attributes of a particular realization of a work, and use the differences in those attributes to signal differences in intellectual or artistic content.
Defining expression as an entity also enables us to draw relationships between specific expressions of a work. We can use the entity called expression to identify, for example, the specific text on which a translation is based, or the specific score used for the performance of a musical composition.
We can also use the entity defined as expression to indicate that the intellectual or artistic content embodied in one manifestation is in fact the same, or substantially the same, as that embodied in another manifestation. If two manifestations embody the same or almost the same intellectual or artistic content, even though the physical embodiment may differ and differing attributes of the manifestations may obscure the fact that the content is similar in both, we can make the common link through the entity defined as expression.
On a practical level, the degree to which bibliographic distinctions are made between variant expressions of a work will depend to some extent on the nature of the work itself, and on the anticipated needs of users and on what the cataloguer can reasonably be expected to recognize from the manifestation being described. Differences in form of expression (e.g., the differences between the expression of a work in the form of musical notation and the expression of the same work in the form of recorded sound) will normally be reflected in the bibliographic record, no matter what the nature of the work itself may be. Variant expressions in the same form (e.g., revised versions of a text) will often be indirectly identified as different expressions because the variation is apparent from the data associated with an attribute used to identify the manifestation in which the expression is embodied (e.g., an edition statement). Variations that would be evident only from a more detailed analysis and comparison of expressions (e.g., variations between several of the early texts of Shakespeare's Hamlet) would normally be reflected in the data only if the nature or stature of the work warranted such analysis, and only if it was anticipated that the distinction would be important to users.
Variations within substantially the same expression (e.g., slight variations that can be noticed between two states of the same edition in the case of hand press production) would normally be ignored or, in specialized catalogues, be reflected as a note within the bibliographic record for the manifestation. However, for some applications of the model (e.g., early texts of rare manuscripts), each variation may be viewed as a different expression.
The third entity defined in the model is manifestation: the physical embodiment of an expression of a work.
The entity defined as manifestation encompasses a wide range of materials, including manuscripts, books, periodicals, maps, posters, sound recordings, films, video recordings, CD-ROMs, multimedia kits, etc. As an entity, manifestation represents all the physical objects that bear the same characteristics, in respect to both intellectual content and physical form.
When a work is realized, the resulting expression of the work may be physically embodied on or in a medium such as paper, audio tape, video tape, canvas, plaster, etc. That physical embodiment constitutes a manifestation of the work. In some cases there may be only a single physical exemplar produced of that manifestation of the work (e.g., an author's manuscript, a tape recorded for an oral history archive, an original oil painting, etc.). In other cases there are multiple copies produced in order to facilitate public dissemination or distribution. In those cases there is normally a more formal production process involved, and a publisher, producer, or distributor takes responsibility for the process. In other cases there may be only a limited number of copies made of an original exemplar for purposes such as private study (e.g., a dubbing of an original recording of a piece of music), or preservation (e.g., a photocopy produced on permanent paper of an author's original typescript). Whether the scope of production is broad (e.g., in the case of publication, etc.) or limited (e.g., in the case of copies made for private study, etc.), the set of copies produced in each case constitutes a manifestation. All copies produced that form part of the same set are considered to be copies of the same manifestation.
The boundaries between one manifestation and another are drawn on the basis of both intellectual content and physical form. When the production process involves changes in physical form the resulting product is considered a new manifestation. Changes in physical form include changes affecting display characteristics (e.g., a change in typeface, size of font, page layout, etc.), changes in physical medium (e.g., a change from paper to microfilm as the medium of conveyance), and changes in the container (e.g., a change from cassette to cartridge as the container for a tape). Where the production process involves a publisher, producer, distributor, etc., and there are changes signaled in the product that are related to publication, marketing, etc. (e.g., a change in publisher, repackaging, etc.), the resulting product may be considered a new manifestation. Whenever the production process involves modifications, additions, deletions, etc. that affect the intellectual or artistic content, the result is a new manifestation embodying a new expression of the work.
Changes that occur deliberately or even inadvertently in the production process that affect the copies result, strictly speaking, in a new manifestation. A manifestation resulting from such a change may be identified as a particular "state" or "issue" of the publication.
Changes that occur to an individual copy after the production process is complete (e.g., the loss of a page, rebinding, etc.) are not considered to result in a new manifestation. That copy is simply considered to be an exemplar (or item) of the manifestation that deviates from the copy as produced.
Defining manifestation as an entity enables us to name and describe the complete set of items that result from a single act of physical embodiment or production. The entity manifestation serves to describe the shared characteristics of copies of a particular publication, edition, release, etc., as well as to describe unique productions such as manuscripts, original oil paintings, etc.
With the entity defined as manifestation we can describe the physical characteristics of a set of items and the characteristics associated with the production and distribution of that set of items that may be important factors in enabling users to choose a manifestation appropriate to their physical needs and constraints, and to identify and acquire a copy of that manifestation.
Defining manifestation as an entity also enables us to draw relationships between specific manifestations of a work. We can use the relationships between manifestations to identify, for example, the specific publication that was used to create a microreproduction.
The fourth entity defined in the model is item: a single exemplar of a manifestation.
The entity defined as item is a concrete entity. It is in many instances a single physical object (e.g., a copy of a one-volume monograph, a single audio cassette, etc.). There are instances, however, where the entity defined as item comprises more than one physical object (e.g., a monograph issued as two separately bound volumes, a recording issued on three separate compact discs, etc.).
In terms of intellectual content and physical form, an item exemplifying a manifestation is normally the same as the manifestation itself. However, variations may occur from one item to another, even when the items exemplify the same manifestation, where those variations are the result of actions external to the intent of the producer of the manifestation (e.g., damage occurring after the item was produced, binding performed by a library, etc.).
Defining item as an entity enables us to separately identify individual copies of a manifestation, and to describe those characteristics that are unique to that particular copy and that pertain to transactions such as circulation, etc. involving that copy.
Defining the entity called item also enables us to draw relationships between individual copies of manifestations.
The fifth entity defined in the model is person: an individual. The entity defined as person encompasses individuals that are deceased as well as those that are living.
For the purposes of this study persons are treated as entities only to the extent that they are involved in the creation or realization of a work (e.g., as authors, composers, artists, editors, translators, directors, performers, etc.), or are the subject of a work (e.g., as the subject of a biographical or autobiographical work, of a history, etc.).
Defining the entity person enables us to name and identify the individual in a consistent manner, independently of how the individual's name appears on or in any particular expression or manifestation of a work.
Defining person as an entity also enables us to draw relationships between a specific person and a work or expression of a work for which that person may be responsible, or between a work and the person that is the subject of the work.
The sixth entity defined in the model is corporate body: an organization or group of individuals and/or organizations acting as a unit.
The entity defined as corporate body encompasses organizations and groups of individuals and/or organizations that are identified by a particular name, including occasional groups and groups that are constituted as meetings, conferences, congresses, expeditions, exhibitions, festivals, fairs, etc. The entity also encompasses organizations that act as territorial authorities, exercising or claiming to exercise government functions over a certain territory, such as a federation, a state, a region, a local municipality, etc. The entity encompasses organizations and groups that are defunct as well as those that continue to operate.
For the purposes of this study corporate bodies are treated as entities only to the extent that they are involved in the creation or realization of a work (e.g., as the sponsors or endorsers of a work, etc.), or are the subject of a work (e.g., as the subject of a history, etc.).
Defining the entity corporate body enables us to name and identify the organization or group in a consistent manner, independently of how the name of the organization or group appears on or in any particular expression or manifestation of a work.
Defining corporate body as an entity also enables us to draw relationships between a specific corporate body and a work or expression of a work for which that corporate body may be responsible, or between a work and the corporate body that is the subject of the work.
The seventh entity defined in the model is concept: an abstract notion or idea.
The entity defined as concept encompasses a comprehensive range of abstractions that may be the subject of a work: fields of knowledge, disciplines, schools of thought (philosophies, religions, political ideologies, etc.), theories, processes, techniques, practices, etc. A concept may be broad in nature or narrowly defined and precise.
For the purposes of this study concepts are treated as entities only to the extent that they are the subject of a work (e.g., as the subject of a philosophical treatise, of a critique of a school of thought, etc.).
Defining the entity concept enables us to name and identify the concept in a consistent manner, independently of the presence, absence, or form of the name for that concept that appears on or in any particular expression or manifestation of a work.
Defining concept as an entity also enables us to draw a relationship between a work and the concept that is the subject of the work.
The eighth entity defined in the model is object: a material thing.
The entity defined as object encompasses a comprehensive range of material things that may be the subject of a work: animate and inanimate objects occurring in nature; fixed, movable, and moving objects that are the product of human creation; objects that no longer exist.
For the purposes of this study objects are treated as entities only to the extent that they are the subject of a work (e.g., as the subject of a scientific study, etc.).
Defining the entity object enables us to name and identify the object in a consistent manner, independently of the presence, absence, or form of the name for that object that appears on or in any particular expression or manifestation of a work.
Defining object as an entity also enables us to draw a relationship between a work and the object that is the subject of the work.
The ninth entity defined in the model is event: an action or occurrence.
The entity defined as event encompasses a comprehensive range of actions and occurrences that may be the subject of a work: historical events, epochs, periods of time, etc.
For the purposes of this study events are treated as entities only to the extent that they are the subject of a work (e.g., the subject of an historical treatise, of a painting, etc.).
Defining the entity event enables us to name and identify the event in a consistent manner, independently of the presence, absence, or form of the name for that event that appears on or in any particular expression or manifestation of a work.
Defining event as an entity also enables us to draw a relationship between a work and the event that is the subject of the work.
The tenth entity defined in the model is place: a location.
The entity defined as place encompasses a comprehensive range of locations: terrestrial and extra-terrestrial; historical and contemporary; geographic features and geo-political jurisdictions.
For the purposes of this study places are treated as entities only to the extent that they are the subject of a work (e.g., the subject of a map or atlas, or of a travel guide, etc.).
Defining the entity place enables us to name and identify the place in a consistent manner, independently of the presence, absence, or form of the name for that place that appears on or in any particular expression or manifestation of a work.
Defining place as an entity also enables us to draw a relationship between a work and the place that is the subject of the work.
The examples used in sections 3.2.1 through 3.2.4 to illustrate the entities work, expression, manifestation, and item showed the entities primarily as integral units (e.g., Shakespeare’s Romeo and Juliet as an example of a work, a particular performance of Schubert's Trout quintet as an expression, etc.). The structure of the model, however, permits us to represent aggregate and component entities in the same way as we would represent entities that are viewed as integral units. That is to say that from a logical perspective the entity work, for example, may represent an aggregate of individual works brought together by an editor or compiler in the form of an anthology, a set of individual monographs brought together by a publisher to form a series, or a collection of private papers organized by an archive as a single fond. By the same token, the entity work may represent an intellectually or artistically discrete component of a larger work, such as a chapter of a report, a segment of a map, an article in a journal, etc. For the purposes of the model, entities at the aggregate or component level operate in the same way as entities at the integral unit level; they are defined in the same terms, they share the same characteristics, and they are related to one another in the same way as entities at the integral unit level. Sections 5.3.1.1., 5.3.2.1, 5.3.4.1, and 5.3.6.1 provide additional information on aggregate and component entities in the context of whole/part relationships.
