> For the complete documentation index, see [llms.txt](https://docs.opendatadiscovery.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.opendatadiscovery.org/features/data-discovery.md).

# Data Discovery

The **Data Discovery** section of ODD Platform is the home for finding entities in the catalog. The role is durable: anything that helps a user **locate** existing data — by typing a term, by walking a known structure, or by landing on the home page — belongs here. The section sits at the **operator-and-user front door**: most catalog interactions begin with one of the two entry paths surfaced from this pillar.

ODD covers Data Discovery fully — both entry paths ship today, and the platform's home page renders them side by side as the catalog's first-encounter view. See the [Data Governance map](/introduction/main-concepts.md#data-governance-map) for the position of Data Discovery in the overall pillar set.

Open it from the top-level navigation **Catalog** (Search-first landing) or **Directory** (hierarchy-first level-1 view). The Catalog Overview page surfaces both entry paths inline.

![Catalog Search results — entity-class tabs along the top (All / My Objects / Datasets / Transformers / Data Consumers / Data Inputs / Quality Tests / Groups / Relationships) with per-class counts; the Filters left-rail exposes Datasource / Namespace / Owner / Groups / Statuses facets. The result list shows mixed entity classes (LOOKUP\_TABLE, ENTITY\_RELATIONSHIP, DEG, DATASET, TRANSFORMER) — search and faceted filtering are how operators move from "I want a user-related entity" to a specific row.](/files/r9UgVVgM77UxaQCBTDZU)

## Subsections

The catalog's two entry paths plus the per-feature surfaces that mark up, classify, and signal freshness on the entities they reach.

**Discovery entry paths**

* [**Catalog Overview page**](/features/data-discovery/catalog-overview.md) — the catalog's **home page**. A unified surface that combines Search, the Directory's level-1 cards, Top tags, Domains, the per-class Entities report, the Recommended quick-jumps, and (when authentication is on) the Owner-association request. Most catalog sessions start here.
* [**Directory**](/features/data-discovery/directory.md) — the catalog's **browse-oriented** entry point. Four-level drill-down (data source types → data sources → entity types → entities) backed by `/api/directory`. Use it when you know the *kind* of source but not the specific instance, when you're auditing per-source coverage, or when you're walking a teammate through the catalog.
* [**Search and Filtering**](/features/data-discovery/search.md) — the catalog's **query-oriented** entry point. Free-text search across entity names plus seven facets (Datasource / Type / Namespace / Owner / Tag / Groups / Statuses). The query-driven counterpart to the Directory.

**Per-entity detail surface**

* [**Data entity detail page**](/features/data-discovery/entity-detail-page.md) — the destination of every catalog discovery. Covers the Overview tab composition, the class-driven panel matrix that decides which panels and tabs appear, the class/type badges in the header, the sidebar list truncation (Tags / Terms / Groups), and the per-panel permission map. The container surface that the annotation features below render onto.

**Annotating discovered entities**

* [**Entity description**](/features/data-discovery/entity-description.md) — operator-authored Markdown description on every data entity. The primary free-text annotation surface; rendered on the Overview tab and surfaced as the preview snippet on search-result rows, Recommended-tile cards, and Directory-level-4 entity rows. Carries a load-bearing security caveat on the platform's no-write-time-sanitisation posture across six Markdown surfaces.
* [**Custom metadata**](/features/data-discovery/custom-metadata.md) — operator-curated typed key/value fields per data entity, plus the deployment-shared field catalogue that backs the autocomplete picker. Covers the seven supported field types, INTERNAL versus EXTERNAL (collector-ingested) origin, and four load-bearing caveats (silent no-op write, dropped `active` flag, unauthenticated catalogue enumeration, forensic silence on mutations).
* [**Per-column annotation**](/features/data-discovery/per-column-annotation.md) — the column-level counterparts to the entity-level annotation surfaces on a dataset's Structure tab — description, tags, glossary terms, enum values, and business name editors per column. Covers the per-sub-editor permissions, the audit-feed events each sub-editor emits, and three operator-visible write-path caveats (a SecurityConstants wiring bug that silently 403s the field-level Add-term button for users with the documented permission, a bulk-replace enum-values endpoint disguised as create-one, and a tags PUT that silently clears every operator-curated tag on empty submission).
* [**Manual Object Tagging**](/features/data-discovery/tagging.md) — apply tags to data entities and columns; the read-side counterpart to the Management → Tags vocabulary curation. Tags drive the Tag facet on Search and the Top tags chip strip on the Catalog Overview.
* [**Data Entity Groups & Domains**](/features/data-discovery/groups-domains.md) — logical containers for related entities, plus the Domain framing that surfaces flagged DEGs on the Catalog Overview's Domains section. Includes the relationship to ML Experiments.
* [**Business names**](/features/data-discovery/business-names.md) — alternative human-readable labels for data entities and dataset fields, surfaced alongside the technical name everywhere the entity is rendered.
* [**Data Entity Statuses**](/features/data-discovery/statuses.md) — `UNASSIGNED` / `DRAFT` / `STABLE` / `DEPRECATED` / `DELETED` lifecycle markers; surface as a Search facet, drive an Activity-feed event, and trigger a soft-delete TTL handled by the housekeeping job.
* [**Data Entity Attachments**](/features/data-discovery/attachments.md) — files (PDFs, CSVs, images) and remote-URL links attached to data entities for additional context. Storage backend operator-configurable; LOCAL is ephemeral.

**Specialty cataloguing**

* [**Vector Store metadata**](/features/data-discovery/vector-stores.md) — vector-typed datasets recognised as a first-class catalog primitive (dedicated `Vector Store` dataset type plus `Vector` column data type), surfaced today via the PostgreSQL `pgvector` adapter.

**Change and freshness signals**

* [**Dataset schema diff**](/features/data-discovery/schema-diff.md) — visual side-by-side comparison of dataset schema revisions, with backwards-incompatible changes additionally raising an alert.
* [**Metadata stale**](/features/data-discovery/metadata-stale.md) — per-entity orange clock icon flagging entities not re-ingested for longer than `odd.data-entity-stale-period` (default 7 days). A discovery-time freshness prompt; not a runtime alert.

## Why this is a separate pillar

For how Data Discovery relates to the other governance pillars (Data Modelling, 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.

## Where to next

* If you know what you're looking for and want to type a term → [Search and Filtering](/features/data-discovery/search.md).
* If you don't know the exact name and want to drill down through known structure → [Directory](/features/data-discovery/directory.md).
* For the surface that every discovery lands on — Overview tab composition, class-driven panels, badges, sidebar truncation, permissions → [Data entity detail page](/features/data-discovery/entity-detail-page.md).
* If you want to label an entity for cross-cutting discovery → [Manual Object Tagging](/features/data-discovery/tagging.md).
* If you want to gather related entities into a logical group or surface a domain on the home page → [Data Entity Groups & Domains](/features/data-discovery/groups-domains.md).
* For the broader catalog vocabulary (Data Entity, Plugin, Push adapter, …) → [Main Concepts](/introduction/main-concepts.md).
* For the position of Data Discovery among the other governance pillars → [Main Concepts → Data Governance map](/introduction/main-concepts.md#data-governance-map).