feat: add tip on multi-table transactions in Unity Catalog

[fusionet24]

Adds a short explainer for transactions on Unity Catalog managed Delta tables, which went GA on 22 July 2026. Nothing in site/tips/ covers it yet.

Source: July 2026 platform release notes.

What's in it

site/tips/Unity Catalog/Transactions.qmd

• The problem — three statements that each commit on their own leave tables disagreeing when the middle one fails.
• Before you begin — DBR 18.0+, UC managed tables, catalogManaged on every write target.
• Working example — a two-table funds transfer plus an audit log:
  1. Create the tables with delta.feature.catalogManaged, add a CHECK (balance >= 0) constraint, seed two accounts.
  2. Run a transfer in BEGIN ATOMIC ... END; and read back the committed balances.
  3. Run an overdraft where the audit insert and the credit succeed and the last statement trips the constraint — then verify both earlier writes were undone. That's the demonstration the feature lives or dies on.
  4. Rewrite it to fail fast with SIGNAL instead of doing work and discarding it.
  5. Clean up with DROP SCHEMA ... CASCADE.
• Choose a mode — BEGIN ATOMIC (row-level conflicts, automatic rollback) vs BEGIN TRANSACTION (table-level, manual commit), with a recommendation rather than a survey.
• Behaviour and limits — repeatable reads via snapshot pinning, optimistic concurrency, one Delta log entry per transaction, no DDL, no time travel, no path-based access, 100-table and 48-hour ceilings.

Every claim is checked against the Transactions, Catalog commits, and SIGNAL reference pages, all linked from the tip.

Also

• site/staticwebapp.config.json: adds the /s/transactions short link, following the existing /s/dml-privileges pattern.

Notes

• Prose follows Google developer documentation style: sentence-case headings, second person, imperative steps, present tense. This differs from the title-case headings in earlier tips.
• Quarto isn't available in this environment, so the page wasn't rendered. Front matter parses as valid YAML, code fences and callout divs are balanced, and the file structure matches the existing tips. The JSON config was validated with a parser.

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Generated by Claude Code

[Copilot]

🟢 Approval recommended

The changes are self-contained documentation + a redirect entry, and the added content/config appears structurally correct and consistent with existing tips.

Pull request overview

Adds a new tip page documenting how to use multi-table transactions with Unity Catalog managed Delta tables, including an end-to-end rollback demonstration and guidance on choosing transaction modes. It also adds a short-link redirect so the tip can be referenced via a stable /s/transactions URL.

Changes:

• Add a new Quarto tip explaining BEGIN ATOMIC ... END; multi-statement transactions on UC-managed Delta tables, with examples for rollback and SIGNAL.
• Add a Static Web Apps redirect for /s/transactions to the rendered tip page.

File summaries

File	Description
site/tips/Unity Catalog/Transactions.qmd	New tip covering UC-managed Delta transactions, including setup, rollback demo, and mode selection guidance.
site/staticwebapp.config.json	Adds /s/transactions short-link redirect to the Transactions tip.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0
• Review effort level: Lite

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