a9f3c50863
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>
1.8 KiB
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Use ModifyAll / DeleteAll instead of per-row Modify / Delete in a loop
Description
ModifyAll and DeleteAll are the bulk APIs. Per the upstream guidance, they "execute as single SQL statements" when the table supports it — one round-trip updates or deletes every row in the filtered set. The anti-pattern is the loop equivalent: FindSet followed by per-row Modify/Delete, where the runtime issues one write per row. On a production-scale table the difference is the difference between a single statement and N statements.
Best Practice
When the loop body does nothing more than assign a constant value (or a value computed once) to one or more fields, replace the loop with ModifyAll("Field 1", Value1) — and chain additional ModifyAll calls for additional fields. The same shape applies to DeleteAll. Be aware that the bulk APIs can regress to row-by-row execution for tables with certain trigger or media-field configurations (see triggers-and-media-field-regress-modifyall.md); when that regression applies, multiple ModifyAll calls become more expensive than one manual loop, so the choice is conditional, not absolute.
See sample: prefer-modifyall-over-per-row-modify.good.al.
Anti Pattern
if SalesLine.FindSet() then repeat SalesLine.Validate("Unit Price", NewPrice); SalesLine.Modify(true); until SalesLine.Next() = 0; — N writes when one would do. The pattern is easy to introduce when the loop initially does per-row computation and is later simplified to assign a constant; the loop scaffolding survives the simplification.
See sample: prefer-modifyall-over-per-row-modify.bad.al.