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CSA Loom — the Microsoft Fabric experience for Azure tenants where Fabric isn't yet available: lakehouses, warehouses, notebooks, semantic models, Activator rules, Data Agents, across Commercial, GCC, GCC-High, and DoD IL5

Purview governance (classic Data Map)

Loom's governance and catalog surfaces — catalog browse/search, asset detail, lineage, glossary, collections, and sources/scans — call the classic Microsoft Purview Data Map data plane through the Console managed identity. This guide walks the register → scan → classify → discover loop in the Loom UI, one-for-one with the classic Purview governance portal.

When to use it

  • Discover what data exists across the estate and where it lives.
  • Classify sensitive data (credit-card, national-ID, etc.) automatically during scans.
  • Trace lineage from a report back through pipelines to source tables.
  • Curate with a business glossary and organize sources into collections.

Why classic Data Map

The Loom Purview client targets the API the ARM-provisioned account actually exposes (host {account}.purview.azure.com, Atlas 2.2 / scanning data plane), not the unified-catalog -api host that a classic account does not resolve. See Purview setup for the exact endpoints and token scope.

Step-by-step: register, scan, classify, discover

  1. Register a source. In the governance surface go to Data Map → Data sources and choose New source (e.g. ADLS Gen2, Azure SQL, Blob). Map it to a collection — this is where discovered metadata lands. Registering gives Purview the address of the source.
  2. Run a scan. Select New scan under the source. Provide a meaningful name, choose a credential (prefer the Purview managed identity, then user-assigned MI, then service principal — least privilege), pick the integration runtime, and Test connection.
  3. Scope and rule set. Optionally scope to specific folders/tables. Choose a scan rule set — the set of system + custom classifications the scan checks (credit card, passport, SWIFT, etc.). Create a new rule set inline if needed.
  4. Trigger. Choose run-once or a schedule, then Save and run. Classifications are applied to column and file assets automatically (table assets get classifications via their columns; apply table-level ones manually). System rules require ≥ 8 distinct values in a column before matching.
  5. Discover. Once ingestion completes, search the catalog by keyword, open an asset detail page to see schema + applied classifications, and open lineage to walk upstream/downstream (direction=BOTH).
  6. Curate. Add glossary terms and align assets to friendly business terms; organize sources into collections for governance at the right scope.

Honest infra gate

If LOOM_PURVIEW_ACCOUNT isn't set (or the Console UAMI lacks the Atlas/Graph app-roles), the governance surface shows a MessageBar naming the account env var and the bootstrap step that grants the roles. The catalog/lineage/scan UI still renders so the workflow is visible.

Tip

Keep classifications meaningful — unnecessary labels look noisy to consumers. Configure the scan rule set once and correctly: editing a custom classification or rule set triggers a full (costly) rescan.

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