bcquality/microsoft/knowledge/privacy/data-classification-required-on-pii-fields.md
Jesper Schulz-Wedde a9f3c50863 Regenerate microsoft/knowledge from upstream BCApps instructions
The previous LLM-generated knowledge files contained factual
hallucinations. The most visible was the claim that `FindFirst` /
`FindLast` "forces a full-table scan" on an unfiltered record - it does
not; those APIs return a single row via the current key.

Other inaccuracies the audit found and fixed:

* `FindSet(true)` was described as "taking a LockTable". The correct
  upstream phrasing is that `FindSet(true)` sets
  `ReadIsolation::UpdLock` on the read. UpdLock and LockTable are
  related but distinct mechanisms.
* The list of production-scale tables had been invented beyond the
  upstream source (e.g. "Detailed Cust. Ledg. Entry") without a
  citation. The regenerated list matches the ten tables upstream lists
  with their P95 row counts.
* `SetLoadFields` guidance had been augmented with an extra mechanism
  claim ("the database resolves the filter using the index without
  hydrating the value") not present in upstream.

Approach: full regeneration of `microsoft/knowledge/` from the six
upstream BCApps Code Review instruction files, with Microsoft Learn /
the AL language reference as a secondary source. Every claim in every
regenerated file is anchored to a verbatim upstream quote (or a Learn
URL); the audit trail lives in artifacts/trace-<domain>.json on the
session workspace.

The PR #11 transaction/error-handling cluster is preserved verbatim:

* performance/understand-implicit-transaction-boundary.md
* performance/codeunit-run-as-atomic-sub-operation.{md,good.al,bad.al}
* performance/codeunit-run-requires-prior-commit-inside-transaction.{md,good.al,bad.al}
* performance/use-tryfunction-for-error-catching-not-rollback.{md,good.al,bad.al}
* performance/avoid-commit-inside-loops.{md,good.al,bad.al}
* security/commitbehavior-attribute-scopes-explicit-commits.{md,good.al,bad.al}
* testing/transactionmodel-attribute-governs-test-transactions.{md,good.al,bad.al}

These articles already cite Microsoft Learn and were carefully
cross-referenced; the regeneration skips their topics rather than
duplicating them.

File counts after regeneration:

  performance   35 .md  (5 preserved + 30 new)
  privacy       17 .md
  security      18 .md  (1 preserved + 17 new)
  style         33 .md
  testing        1 .md  (preserved)
  ui            19 .md
  upgrade       18 .md

Total 141 atomic knowledge files, each strictly one rule. All pass
.github/scripts/validate_frontmatter.py with 0 errors and 0 warnings.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-05-21 09:53:09 +02:00

1.6 KiB

bc-version domain keywords technologies countries application-area
all
privacy
data-classification
pii
gdpr
customer-content
table-field
under-classified
al
w1
all

DataClassification is required on table fields containing sensitive data

Description

DataClassification is the AL property that tells the platform what kind of data a table field stores so that telemetry, GDPR data-subject requests, and the platform's audit surfaces can treat it correctly. It is required on any field that holds personal or customer data. The default value SystemMetadata means "no user or customer data" — applying it to a field that actually holds PII (an email address, a customer name, an employee code) is an under-classification and a privacy bug, even though the code still compiles.

Best Practice

Set DataClassification to the value that matches the data the field actually stores. A Customer."E-Mail"-style field is CustomerContent (data belonging to the tenant's customers); a personal identifier such as an employee number or user ID is EndUserIdentifiableInformation or EndUserPseudonymousIdentifiers depending on whether it is directly identifying. Choose the classification at field definition time — fixing it later is a schema change.

See sample: data-classification-required-on-pii-fields.good.al.

Anti Pattern

Declaring a field that stores PII with DataClassification = SystemMetadata to silence the compiler warning. The field compiles but the platform now treats customer data as system metadata in telemetry, GDPR exports and admin reports.

See sample: data-classification-required-on-pii-fields.bad.al.