Data dictionary
Deduplicated and enriched from PDTF Schemas v3 (base transaction + 16 canonical overlays) and the OPDA Glossary spreadsheets. Each entry carries a suggested RDF URI for use in the ontology workstream.
This page surfaces 1,538 PDTF schema-derived data elements (broad, schema-level). The Logical tier of the Ontology manual documents 41 ontology entities with typed attribute tables, cardinality, identity keys, and ER diagrams (deep, ontology-level). The two are complementary: this dictionary is the raw material; the manual's logical tier is the refined, generator-emitted ontology reference.
- 16 canonical schemas (5 redundant ones excluded)
- 1,538 unique data elements — one entry per unique concept name, deduplicated across all schemas
- 699 entities — objects and arrays (things that exist in the model)
- 840 properties — scalar fields (attributes of entities)
- 54 business terms from the merged OPDA Glossary
- 554 concepts in the generated SKOS scheme
Deliverables
All files generated to source/00-deliverables/semantic-models/.
| File | Size | What it is | Audience |
|---|---|---|---|
data-dictionary-canonical.json | ≈ 1.8 MB | Machine-readable: 8,458 property-path entries across the 16 canonical schemas (one row per schema×path occurrence, not deduplicated). The browser above shows the 1,538 deduplicated concepts. | Engineers, code generators |
data-dictionary.json | 3.0 MB | Original extraction including derived/superseded schemas (14,287 entries). Kept for transparency — do not use for counts. | Audit only |
data-dictionary.md | ≈ 110 KB | Human-readable: per-schema tables, deduplicated to unique leaf names, organised by bounded context. | Engineers, BAs, reviewers |
audit.json | ≈ 2 KB | What the inflation was, why, and the corrected figures. | Anyone reviewing numbers |
glossary-merged.json | 20 KB | Merged of the two OPDA Glossary.xlsx files (PoC + Technical WG), deduplicated to 54 unique terms. | Engineers, modelling |
business-glossary.md | 23 KB | Three-section human glossary: OPDA Glossary terms A–Z, top-level PDTF concepts from schema annotations, external vocabulary (W3C VC, DID, ToIP). | Stakeholders, working groups, new joiners |
business-glossary.ttl | 164 KB | SKOS Concept Scheme — 554 concepts. Loads directly into Protégé / GraphDB / TopBraid for the ontology work. | Ontology engineers |
Canonical schema inventory
| Schema | File | Bounded context | Unique leaves |
|---|---|---|---|
| Base Transaction | pdtf-transaction.json | Base — spans all contexts | 1,557 |
| BASPI v5 | baspi5.json | Estate Agency | 318 |
| Residential Data Schema | rds.json | Property Data Services | 196 |
| Property Info Questionnaire | piq.json | Surveying | 184 |
| Property Information Form | ta6.json | Conveyancing | 178 |
| NTS Sales v2 | nts2.json | Estate Agency | 160 |
| Leasehold Property Enquiry | lpe1.json | Conveyancing | 136 |
| Local Authority Search | con29R.json | Property Data Services | 125 |
| NTS Lettings v2 | ntsl2.json | Estate Agency | 124 |
| Leasehold Information Form | ta7.json | Conveyancing | 98 |
| Fittings & Contents | ta10.json | Conveyancing | 90 |
| Mortgage Enquiries | fme1.json | Mortgage Lending | 78 |
| Office Copy | oc1.json | Property Data Services | 68 |
| Drainage & Water | con29DW.json | Property Data Services | 34 |
| SR24 | sr24.json | Property Data Services | 7 |
| Local Land Charges | llc1.json | Property Data Services | 3 |
How it was built
Suggested RDF URIs
Every data element carries a suggested RDF URI using the
https://w3id.org/opda/pdtf/ base namespace — not yet registered or
dereferenced, but stable enough to use in draft ontology work.
- Entities (objects / classes):
https://w3id.org/opda/pdtf/class/ClassName - Properties (scalar attributes):
https://w3id.org/opda/pdtf/vocab/propertyName
These will be refined when the upper ontology is defined (see step 2 under
What to do with these deliverables). Cross-context concepts
(e.g., address, name) share a single URI — disambiguation
into context-specific sub-properties is deferred to that step.
Source citations
Every entry in the browser carries a source field (primary schema) and a sources array listing all schemas that define that path. Use the Sources facet to explore which overlays contribute a given element.
The primary sources, with paths:
source/03-standards/schemas/src/schemas/v3/pdtf-transaction.json(base transaction schema)source/03-standards/schemas/src/schemas/v3/overlays/*.json(BASPI v5, TA6, TA7, TA10, NTS2, NTSL2, CON29R, CON29DW, PIQ, RDS, OC1, LLC1, LPE1, FME1, SR24)source/06-research/trust-framework-poc/Glossary.xlsxsource/04-governance-bodies/working-groups/technical/Glossary.xlsx- External: W3C VCDM 2.0, W3C DID 1.0, Trust Over IP Foundation
Cross-context concepts
Many paths appear in three or more overlays — these are the cross-context vocabulary that needs explicit reconciliation in the ontology. Top examples (sorted by spread):
address, name, date, amount,
type, description, reference,
status, provider, title,
property, id, required, code,
category …
Full list with which overlays contain each: see the
"Cross-context concepts" section of
source/00-deliverables/semantic-models/business-glossary.md.
What to do with these deliverables
- Have an editorial pass over
business-glossary.mdwith the Technical Working Group — reconcile the OPDA Glossary terms with the property-data terms extracted from the schemas. - Define the upper ontology — pick the core classes (Transaction,
Property, Participant, Claim, Document, Form, Search) and align with W3C VC.
Register the
https://w3id.org/opda/pdtf/namespace and replace the suggested URIs with resolvable ones. - Per-overlay JSON-LD contexts — for each of the
16 canonical overlays, author a
@contextthat maps JSON property names to ontology terms. Start withbaspi5.jsonas the worked example. - Generate SHACL shapes from the JSON Schema validation rules. Most rules (required, enum, pattern, type) translate mechanically.
- Disambiguate cross-context names — for each name appearing in multiple overlays, decide whether it refers to the same concept (single URI) or to context-specific concepts (separate URIs with mapping).
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