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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

Loom Warehouse Editor — Fabric-parity spec

Captured 2026-05-26. Source: Fabric Data Warehouse documentation. Note: catalog agent a25d745464518b765 mistakenly documented Eventhouse (KQL DB) — those findings went into eventhouse-parity-spec.md. This file documents the actual Fabric Data Warehouse UI.

Overview

Fabric Data Warehouse = lake-centric distributed T-SQL warehouse (Polaris engine, similar to Synapse Serverless behavior). Loom's equivalent = the existing Synapse Dedicated SQL Pool editor (better Loom-equivalent for "warehouse-shaped" workloads).

Fabric Warehouse UX

Top toolbar

  • Tabs: switches between Object Explorer modes (Schema view, Model view, Query view)
  • + New SQL query (opens new query tab)
  • Save / Save as / Share buttons
  • Refresh schema cache
  • Settings / Workspace context

Left — Object Explorer

  • Schemas (dbo, custom)
  • Tables (each: schema icon, table name, expandable to columns with types + nullability)
  • Views
  • Stored procedures
  • Functions (scalar + table-valued)
  • Types (user-defined)
  • Right-click on any item: Query top 100 · Drop · Properties · Refresh · Create stored proc with this · ...
  • "Search objects" box at top

Main pane — Query view

  • Monaco-based SQL editor with T-SQL grammar + intellisense (column auto-complete from schema)
  • Run button + dropdown (Run query / Run selection / Explain plan)
  • Cancel query button when active
  • Results grid below editor:
  • Column types annotation in headers (varchar, int, datetime, etc.)
  • Sortable + filterable columns
  • Export menu: CSV / JSON / Parquet
  • Visualize toggle (renders quick chart from results)
  • Row count + execution time
  • Messages tab alongside Results (errors, warnings, info, query plan output)

Main pane — Model view (relationships)

  • Canvas with table cards + relationship lines
  • Drag to create FK relationships
  • Right-side properties pane for selected relationship (cardinality, cross-filter direction)

Main pane — Visual Query Designer

  • Drag-and-drop query builder (like SSIS query designer)
  • Joins via canvas
  • Generates T-SQL behind the scenes

Settings tab

  • Workspace context, capacity binding
  • Refresh policies
  • Security: workspace roles, RLS, column-level security, dynamic data masking

What Loom has

  • ✅ synapse-dedicated-sql-pool editor with: Run T-SQL · Resume-on-demand · Auto-pause Logic App
  • ✅ /api/items/synapse-dedicated-sql-pool/{id}/query (real T-SQL)
  • ✅ /api/items/synapse-dedicated-sql-pool/{id}/schema (schema browser)
  • ✅ /api/items/warehouse/[id]/query (proxy to dedicated pool)
  • ⚠️ Warehouse editor in phase3-editors.tsx is a thin wrapper, missing the rich Object Explorer + Visual Query Designer + Model view

Gaps for parity

  1. Object Explorer tree — currently flat list, needs Schemas → Tables/Views/Procs/Funcs hierarchy
  2. Multi-tab SQL editor — only one query window at a time today
  3. Results grid features — column types in header, sort/filter, export to CSV/JSON/Parquet, visualize toggle
  4. Messages tab — separate pane for errors/warnings/plan
  5. Model view — relationship canvas (Power BI-style)
  6. Visual Query Designer — drag-drop query builder

Backend

All Synapse Dedicated SQL Pool calls already work. New BFF routes needed: - /api/items/warehouse/[id]/object-tree — full Schemas→Tables→Columns tree via INFORMATION_SCHEMA queries - /api/items/warehouse/[id]/export?format=csv|json|parquet — stream query results to format - /api/items/warehouse/[id]/relationships — read sys.foreign_keys for Model view

Estimated effort

3 sessions: Object Explorer + multi-tab + Results enhancements is 1 session; Model view is 1; Visual Query Designer is 1 (or scope-cut to "view T-SQL of selected tables" if budget tight).