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Link your Semantics

A property does not have to carry its full meaning inline. With the ODCS authoritativeDefinitions attribute, a property can link to a shared semantic concept — a business term defined once, centrally — and the CLI resolves that link and inlines the definition before linting, testing, or exporting the contract.

schema:
  - name: orders
    properties:
      - name: article
        authoritativeDefinitions:
          - type: semantics
            url: http://www.entropy-data.com/ns/main/Article

The referenced concept supplies the description, business name, logical type, and anything else it defines, so every contract that links to it stays consistent by construction.

URL or IRI​

The url of a type: semantics link may be either of the two shapes ODCS allows, and the CLI resolves each differently:

urlResolved as
A path or an absolute URL on the configured host — /demo/semantics/main/product.brandREST URL — fetched directly
An absolute URL on any other host — http://www.entropy-data.com/ns/main/ArticleIRI — an identifier, not an address; looked up through /api/semantics?iri=… on the configured host

An IRI names a concept but is usually not fetchable at its own address, so the CLI never dereferences it directly. It URL-encodes the IRI and asks the configured host to resolve it.

Only type: semantics (and the older semantic and definition) links are resolved. The glossary, ontology and taxonomy types that ODCS v3.2.0 recommends are kept as links: the HTML export shows them, and nothing is merged from them.

Reusable definitions​

type: definition links to a reusable ODCS property definition instead of a semantic concept:

properties:
  - name: customer_email
    authoritativeDefinitions:
      - type: definition
        url: https://example.com/definitions/email.json

A definition URL on a different host is fetched directly and anonymously — a contract may legitimately point at a third-party URL, and the API key is never sent across hosts.

When a property carries several links, the highest-precedence one wins and is the only one fetched: semantics → semantic (the legacy singular spelling, still accepted) → definition → businessDefinition.

Reference a file​

A link may also point at a file next to the contract instead of a server. This is the shape to reach for when the business meaning of a field is described in the same repository, and no server is involved. There are two ways to write it, depending on where the definition lives.

A property in another contract​

Use a <file>#<fragment> reference when the meaning belongs to a property of another contract — typically a business-level contract that a technical contract materializes:

# top-artists-by-year-view.odcs.yaml
properties:
  - name: artist_name
    logicalType: string
    physicalType: character
    authoritativeDefinitions:
      - type: businessDefinition
        url: top-artists-by-year.odcs.yaml#schema/top_artists_by_year_ba/properties/artist_name

The technical contract keeps logicalType, physicalType, and primaryKey, and inherits businessName, description, examples, and everything else the business attribute defines. See examples/business-definitions for the full pair.

The fragment walks the referenced contract:

#schema/<schema>/properties/<property>[/properties/<nested>]…[/items]

Each step matches on id first and falls back to name. Contracts that carry stable ids should reference by id — that keeps the link intact when a human-readable name changes. The fragment has to end at a property; it cannot point at a schema object.

A file that is the definition​

Leave the fragment off, and the file is the definition: it holds the elements of the property directly, with no contract around them. This is the shape for a glossary kept as one file per term:

# definitions/shipment_id.odcs.yaml
businessName: Shipment ID
description: Unique identifier for each shipment.
logicalType: string
examples:
  - 123e4567-e89b-12d3-a456-426614174000
# shipments.odcs.yaml
properties:
  - name: sid
    physicalType: uuid
    authoritativeDefinitions:
      - type: businessDefinition
        url: definitions/shipment_id.odcs.yaml

A fragment-less url is read from disk when it names a .yaml, .yml, or .json file. Everything else without a fragment stays what it has always been — a path on the configured host, e.g. url: /definitions/shipment_id.

Both shapes​

The file path is relative to the contract that holds the reference, so a checked-out directory resolves from any working directory. Absolute paths work too. A contract read from an HTTP URL cannot resolve a file reference.

The type of the link says what the reference means; the shape of the url says where it lives. Every resolvable type — semantics, semantic, definition, businessDefinition — accepts a file reference and a URL alike, so the two are never tied together.

Chains resolve: if the referenced business attribute itself links to a glossary file or a semantic concept, that link is resolved before the value is inlined. A cycle between files is reported as an error rather than followed.

How the definition is merged​

The resolved definition fills in only what the property leaves unset — inline values always win:

properties:
  - name: article
    description: The article as sold in the German shop   # kept
    authoritativeDefinitions:                             # supplies logicalType,
      - type: semantics                                   # businessName, tags, …
        url: http://www.entropy-data.com/ns/main/Article

These are never merged, because they belong to the contract author: id, name, authoritativeDefinitions itself, and the properties / items that make up the structure.

This is the same for a link to a semantic concept, a reusable definition, and a business attribute in another file.

Resolution recurses into nested properties and array items, so a link on a deeply nested field resolves too. Successful lookups are cached per run; failures are not, so a transient error retries on the next run.

Configuration​

Environment variablePurpose
ENTROPY_DATA_HOSTThe host that resolves references. Defaults to https://api.entropy-data.com. Falls back to the deprecated DATAMESH_MANAGER_HOST, then DATACONTRACT_MANAGER_HOST.
ENTROPY_DATA_API_KEYSent as x-api-key, and only to the configured host. Falls back to the deprecated DATAMESH_MANAGER_API_KEY, then DATACONTRACT_MANAGER_API_KEY.

An IRI lookup always requires an API key — /api/semantics is API-key only. A REST URL on the configured host uses the key when one is set.

Turning resolution off​

Resolution runs by default on lint, test, ci, changelog, and every export format. Pass --no-inline-references to skip it and work with the contract exactly as written:

datacontract lint --no-inline-references datacontract.yaml
caution

A reference that cannot be resolved rejects the contract — the command fails rather than silently continuing with an incomplete property. If the error is a 401 or 403, the configured host is usually the wrong deployment for that IRI; the message includes the ENTROPY_DATA_HOST to set.

Learn more​