# Data Modelling

The **Data Modelling** section of ODD Platform is the home for operator-curated artefacts that describe how data is *intended* to be used: canonical query examples and the entity-to-entity relationships that collectors extract or that operators define explicitly. The section is intentionally narrow — two child surfaces today — but the role is durable: anything that documents the *contract* of a dataset (how it's queried, how it's connected) belongs here rather than in the per-entity catalog page.

Open it from the top-level navigation **Data Modelling**. The route opens on **Query Examples** by default; a vertical-tabs sidebar switches between Query Examples and Relationships in one click.

## Subsections

* [**Query Examples**](/features/data-modelling/query-examples.md) — operator-curated SQL / KQL / Spark snippets attached to data entities and terms. Surfaces "how the team uses this dataset" as a first-class catalog object instead of leaving it buried in a wiki, with a dedicated faceted search and term-linking workflow.
* [**Relationships**](/features/data-modelling/relationships.md) — entity-to-entity links rendered as ERD diagrams. Covers two relationship classes: `ENTITY_RELATIONSHIP` (foreign-key-style ERD edges between table-class entities) and `GRAPH_RELATIONSHIP` (free-form graph edges, e.g. between Neo4j nodes).

## UI entry points

| Path                                  | What                                                                                         |
| ------------------------------------- | -------------------------------------------------------------------------------------------- |
| `/data-modelling`                     | Redirects to `/data-modelling/query-examples`.                                               |
| `/data-modelling/query-examples`      | Query Examples list + creation surface. RBAC-gated by `QUERY_EXAMPLE_CREATE`.                |
| `/data-modelling/query-examples/{id}` | Query Example details / edit. RBAC-gated by `QUERY_EXAMPLE_UPDATE` + `QUERY_EXAMPLE_DELETE`. |
| `/data-modelling/relationships`       | Relationships list — ERD and graph relationships discovered across all data sources.         |

## Why this is a separate pillar

For how Data Modelling relates to the other governance pillars (Data Discovery, Master Data Management, Data Lineage, Data Glossary, Data Quality), see [Main Concepts → Data Governance map → Pillar differentiation](/introduction/main-concepts.md#pillar-differentiation) — the canonical home for the six-pillar framing. Data Modelling is its own pillar because it captures the *contract* of a dataset (how it's queried, how it's connected) — the dataset itself comes from outside; this pillar records the intent and structure layered on top.

## Where to next

* If you're documenting how a dataset is *queried*, start with [Query Examples](/features/data-modelling/query-examples.md).
* If you're discovering how datasets are *connected* (foreign keys, cross-schema joins, graph references), start with [Relationships](/features/data-modelling/relationships.md).
* For the broader catalog vocabulary (Data Entity, Plugin, Push adapter, …), see [Main Concepts](/introduction/main-concepts.md).


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