Promote knowledge for Microsoft review skills (#153)

Move canonical knowledge for Microsoft-owned review domains into the Microsoft layer and document the skill/knowledge co-location policy.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Jesper Schulz-Wedde <jesper.schulzwedde@microsoft.com>
Copilot-Session: 2a6ea875-d38e-4f30-aadb-0d606f9be231

microsoft/knowledge/data-modeling/validate-table-relation-false-suppresses-rename-propagation.md

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+---
+bc-version: [all]
+domain: data-modeling
+keywords: [validatetablerelation, table-relation, rename, onrename, propagation, dangling-reference, soft-relation]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# `ValidateTableRelation = false` suppresses rename propagation, not just input validation
+
+## Description
+
+Renaming a record updates it in all other locations that reference it through a `TableRelation`, with no code. That guarantee has **two** preconditions, and a field failing either one is silently left holding a key that no longer exists.
+
+First, a `TableRelation` must exist. A field whose value is constructed or computed — a composite key, or a value derived from several fields of the target — cannot declare one, so nothing propagates. The field is still a foreign key in intent, but the platform treats it as an opaque value.
+
+Second, and far less obvious: the relation must not carry `ValidateTableRelation = false`. The property name implies it only governs *input validation*, so it looks safe to disable on a field populated by code that already knows the target is valid. It is not. **Disabling it also switches off rename propagation.** The relation still documents intent and still drives lookups, but it no longer keeps the stored value correct.
+
+Both failures are quiet: no error at rename time, and in the first case no input validation either, so a wrong value is never rejected on write.
+
+This is verified behaviour, not inference. A parent renamed once against a child holding three fields — a normal relation, the same relation with `ValidateTableRelation = false`, and a field with no relation — updates only the first.
+
+See also `owning-table-must-delete-dependents-in-ondelete.md` for the delete half of this asymmetry, and `xrec-is-a-before-image-only-in-some-triggers.md` for why `OnRename` is the one trigger where a hand-written fix-up is reliable.
+
+## Best Practice
+
+Leave `ValidateTableRelation` at its default wherever the stored value must stay correct across a rename. When it must be disabled, or when the relationship cannot be expressed as a `TableRelation` at all, the table owning the referenced key carries an explicit `OnRename` that repoints the dependents itself.
+
+See sample: `validate-table-relation-false-suppresses-rename-propagation.good.al`.
+
+## Anti Pattern
+
+`ValidateTableRelation = false` added to silence a validation error, on a field expected to keep tracking its target. The field stops being maintained on rename, and the defect surfaces much later as a reference to a key that no longer exists.
+
+Detection signal: any `ValidateTableRelation = false` on a field that also declares a `TableRelation`. Ask what repoints the value when the target is renamed; if the answer is "the platform", the finding stands.
+
+See sample: `validate-table-relation-false-suppresses-rename-propagation.bad.al`.