Data Model – Entity Definitions (Version 5.0)

This document defines the conceptual meaning of all entities in the Costasano Heritage Database.

It is the authoritative reference for:

conceptual ER modeling
DBML schema design
Page Schemas and forms
editorial workflows
successor understanding

These definitions describe meaning and responsibility, not implementation details.

If an entity definition is unclear or disputed, implementation must be postponed.

Scope

The conceptual model separates clearly between:

Storage → File
Interpretation of files / sources → Asset
Subjects of research → Object, Person, Organisation
Spatial context → Place
Narrative structure → Chapter

The conceptual flow is:

File → Asset → Research Entity → Place → Chapter

Each layer enriches the previous one without replacing it.

Core Research Entities

Object

Definition

An Object represents a historical, conceptual, or material entity that is the subject of study.

It answers:

“What is the thing we are studying?”

Objects are the primary conceptual anchors of the research.

Examples

An Object may represent:

a sanatorium
a building
a room or architectural element
a document or register
a site or complex
a conceptual or functional unit (e.g. “medical practice”)
an artifact (future research)

What an Object is not

An Object is:

not a digital file
not a person
not an organisation
not a chapter
not a technical record

Structural behavior

Objects are recursive.

Each Object may:

have zero or one parent Object
have zero or more child Objects

This supports hierarchical structures such as:

Room → Building → Site → City

Place relationship

Each Object has one primary Place.

This Place represents:

where the Object exists or existed
the Object’s physical or historical location

Additional contextual places (e.g. “found in”, “stored in”) may be added in future extensions.

Temporal span

Objects may have:

DateFrom
DateTo

These describe the Object’s period of existence or relevance.

Relationships

An Object may:

be documented by multiple Assets
designate one Asset as preferred representation
be linked to Persons with roles
be linked to Organisations with roles
have a Person or Organisation as holder
belong to multiple Chapters
be tagged with Keywords

Purpose

Objects represent the historical “things” being studied and provide the backbone of the research domain.

Person

Definition

A Person represents a historical or contemporary individual with agency.

It answers:

“Who was involved historically?”

Examples

religious sisters
directors
architects
patients
shareholders
board members

What a Person is not

A Person is:

not a MediaWiki user
not an Object
not an organisation

Relationships

A Person may:

play roles in relation to Objects
play roles within Organisations
act as holder of Objects
be documented by Assets (portraits, letters, articles)

Roles belong to relationships, not to the Person entity itself.

Purpose

Persons model historical agency, responsibility, and participation.

Organisation

Definition

An Organisation represents a historical collective actor with institutional continuity.

It answers:

“Which collective body acted or was responsible?”

Examples

religious congregations
companies
associations
institutions
managing bodies

What an Organisation is not

An Organisation is:

not a person
not an Object
not a Place

Relationships

An Organisation may:

play roles in relation to Objects
include Persons with roles
act as holder of Objects
be documented by Assets
be located in a Place

Purpose

Organisations model collective responsibility and institutional continuity.

Spatial Context

Place

Definition

A Place represents a geographical or spatial location.

It answers:

“Where is or did this exist or occur?”

Places provide spatial context only and do not possess agency.

Examples

A Place may represent:

a city
a village
a building
a room
a site or complex
a region or landscape
a country

What a Place is not

A Place is:

not a person
not an organisation
not an Object
not an actor with responsibility

Structural behavior

Places are recursive.

Each Place may:

have zero or one parent Place
have zero or more child Places

Example hierarchy:

Room → Building → Site → City → Region → Country

Geocoding

Places may have:

latitude
longitude

Coordinates describe the Place itself.

Relationships

A Place may:

locate Organisations
locate Objects
provide creation or depiction context for Assets

Purpose

Places provide structured geographic information and prevent misuse of Organisations for spatial data.

Digital Representation and Sources

Asset

Definition

An Asset represents the scholarly interpretation and extended metadata of exactly one File.

It answers:

“How do we interpret and describe this specific digital file as a research source?”

Assets are the human, scholarly layer that gives meaning to files.

Core principle

One Asset corresponds to exactly one File.

This rule is strict.

Each version of a source (TIFF, JPEG, AI‑processed, cropped detail) receives its own Asset.

Examples

An Asset may represent:

a photograph
a scanned document
a cropped detail
a newspaper article
a portrait
a letter or archival record
an AI‑processed derivative

Relationship to Files

An Asset:

always references exactly one File
does not manage storage
does not replace Drupal file handling

Files are storage. Assets are interpretation.

Recursive behavior

Assets are recursive.

An Asset may:

derive from another Asset
have multiple derived children

This models:

versioning
derivative chains
multi‑representation sequences
cross‑media transformations

Relationships to research entities

An Asset may document one or more:

Objects
Persons
Organisations

Spatial context

An Asset may optionally reference a Place to record:

place of creation
place depicted
place of discovery

Publication and citation role

Assets may store:

bibliographic citation text
repository information
permalinks
rights information
publication suitability
AI‑processing status

What an Asset is not

An Asset is:

not a file
not a container of files
not a historical object
not merely technical metadata

Purpose

Assets separate meaning from storage and provide rich research metadata.

Narrative Structure

Chapter

Definition

A Chapter represents a conceptual or narrative unit of interpretation.

It answers:

“Where does this belong in the research story?”

Characteristics

A Chapter:

structures interpretation
is not merely a date range
may be thematic or chronological
may overlap with other chapters

Structural behavior

Chapters are recursive.

A Chapter may contain subchapters.

Temporal span

Chapters may have:

StartYear
EndYear

These describe the narrative period, not the Object’s existence.

Relationships

A Chapter may include multiple Objects. An Object may belong to multiple Chapters.

Purpose

Chapters organize interpretation rather than historical reality.

Typing Entities

ObjectType

Defines the category of Object.

Examples:

Building
Room
Document
Artifact
Collection
Site

Purpose:

supports classification
improves filtering and navigation
does not encode logic

AssetType

Defines what kind of thing the Asset is.

Examples:

Image
Map
Document
Audio
Video
Drawing
Blueprint
Postcard

Purpose:

clarifies the nature of the source
supports UI grouping
does not imply workflow

AssetSourceType

Defines how the Asset was obtained.

Examples:

Scan
Photograph
Archive reproduction
AI‑processed derivative
OCR transcription
Screenshot
Cropped detail

Purpose:

documents provenance
clarifies origin of the digital representation

AssetRole

Defines the role of an Asset relative to an Object.

Examples:

Depicts
Documents
Contains
Shows detail of
Preferred representation
Technical reproduction

Purpose:

clarifies the interpretive relationship
supports multiple Assets per Object

PersonRole

Defines the role of a Person relative to an Object.

Examples:

Architect
Director
Owner
Builder
Patient
Photographer
Author

Purpose:

expresses historical agency
belongs to the relationship, not the Person

OrganisationRole

Defines the role of an Organisation relative to an Object.

Examples:

Managing body
Owner
Builder
Operator
Sponsor
Religious congregation

Purpose:

expresses institutional responsibility

Keywords

Keywords provide flexible thematic tagging.

Examples:

Architecture
Healthcare
Maritime
Industrialisation
Daily life

Purpose:

supports discovery
does not define structure

Supporting Concepts

Holder

Represents the current custodian of an Object.

A holder may be:

a Person
an Organisation

Only one should be used per record.

Treatment of Uncertainty

Uncertainty is expressed through:

wording
ranges
notes
citations

No structural certainty levels are implemented.

Clarification: Object–Asset Relationship

Objects and Assets have a many‑to‑many relationship.

An Object may be documented by one or more Assets.
An Asset may document one or more Objects.

This relationship is expressed through the ObjectAsset junction table, which records:

the Object
the Asset
the AssetRole (e.g. depicts, documents, contains, detail of)
whether the Asset is the preferred representation of the Object

This design ensures that:

a single photograph may document multiple Objects (e.g. a building and its annex)
a single Object may have multiple Assets (historical photo, modern photo, blueprint, document scan, detail crop, AI‑processed version)
the relationship remains contextual and interpretive, not intrinsic to either entity

The Object–Asset link is therefore not stored on the Asset itself, but in the contextual layer, where roles and preferences can be expressed explicitly.

Status

This document defines the agreed conceptual meaning of all entities – Version 5.0.

All ER diagrams, DBML definitions, schemas, and implementations must conform to these definitions.