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18 AL/BC patterns: style, data-modeling, web-services, appsource, breaking-changes, performance, testing (#156)
* Add 18 community AL/BC patterns across style, data-modeling, web-services, appsource, breaking-changes, performance, and testing Contributed by CURABIS ApS, generalized from patterns observed across real AppSource/PTE development. Each article follows the knowledge file format (frontmatter, Description/Best Practice/Anti Pattern, sibling .good.al/.bad.al samples). * Address Jesper Schulz-Wedde's review on PR #156 - Rename 3 articles so their .good.al/.bad.al companion stems match (do-not-change-primary-key, testfield-required-setup-field, al-identifiers-english), fixing the R14 orphan-sample errors. - do-not-change-primary-key.good.al: include Flow in the new table's own primary key so it actually models the discriminating dimension. - al-build-output-must-not-pollute-project-root.md: drop the unsubstantiated AL0197 causal claim and the non-existent al.outputPath setting; reframe as build-artifact hygiene sourced from ALTool --outfolder / al_build outputPath. - prefer-email-module.md: Email Message is Codeunit 8904, not a table; distinguish it from the underlying Sent/Outbox/Draft storage. - file-datatype-saas.md: File.Open/Create/Read/Write fails to compile against a Cloud-scoped project, it does not compile and silently fail at runtime. - namespace-must-be-verified-from-source.md: narrow to "resolve from the referenced object's source or symbols," since source-file line one is not the only authoritative source (symbol packages, comments before the namespace line). - test-data-must-be-random-and-complete.md: drop "assume an empty database" and "collision-free" absolutes; reframe around independence from unrelated business records and reserving explicit values for scenario-defining inputs. - binary-choice-must-be-boolean.md: scope to genuine true/false semantics, not mechanical two-member-enum-to-boolean conversion. - document-report-word-layout.md: scope down to a sourced Microsoft Learn recommendation instead of an unconditional performance guarantee; cite the three Learn pages. - Wire the new articles into their review skills' candidate-selection signals (file-datatype-saas, prefer-email-module, namespace-must-be-verified-from-source, var-parameters-require-an- addressable-variable) so they can actually enter a worklist. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> * Fix dimension-management-wiring.md: ValidateShortcutDimCode and CreateDim do not exist on the current DimensionManagement codeunit Verified against microsoft/BCApps: the real master-table validation procedure is ValidateDimValueCode (or ValidateShortcutDimValues when a DimSetID is also needed), and the real document-side inheritance procedure is GetDefaultDimID, not CreateDim. Caught from Jesper Schulz-Wedde's review thread, which had been partially hidden by GitHub's comment folding. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> * Address second round of Jesper Schulz-Wedde's review on PR #156 - dimension-management-wiring.md/.good.al: split into the two distinct models the article was conflating - master data (Default Dimension records via ValidateDimValueCode/SaveDefaultDim) vs. transactional/ document data (a single Dimension Set ID assembled via AddDimSource + GetDefaultDimID, verified against BCApps' ExchRateAdjmtProcess.Codeunit.al). Added a compiling document-table example alongside the existing master table one. - Deleted api-page-flowfields-must-be-calcfields (.md/.good.al/.bad.al): Microsoft's own FlowFields documentation states a FlowField used as a control's direct source expression is automatically calculated on any page - no API-page exception is documented, and none could be reproduced. - prefer-email-module.bad.al/.md: Codeunit Mail has no Send/GetErrorDesc members; fixed to the real current 7-argument CreateMessage signature, and corrected the claim that the legacy path "still runs" - its base implementation no longer sends anything, only raises integration events. - check-post-line-batch-pattern.md/.good.al: reframed from a universal invariant to the standard shape, naming the real Gen./Item/CA/Res./Job/ Insurance/Mfg. Item/FA Jnl.-Check Line/-Post Line/-Post Batch codeunits it's based on. Added the missing Check Line companion codeunit so the good fixture is internally complete. - test-data-must-be-random-and-complete.good.al: removed leftover "collision-free" wording contradicting the already-corrected article text. - fixed-choice-set-must-use-enum-not-integer.md: removed the reintroduced state-count heuristic ("the line is the state count"), aligned with binary-choice-must-be-boolean.md's semantics-based distinction. - namespace-must-be-verified-from-source.md: removed the false claim that the compiler and AL Language Server use different namespace-resolution rules. - intrinsic-al-functions-must-use-modern-casing.md: removed the unverified claim that PascalCase is the VS Code formatter's default output. Worklist completeness: added cues for the 8 rules in data-modeling, testing, performance, and web-services that had none (Jesper's explicit ask), plus the same gap in all 7 style rules from this PR (not explicitly named this round, but the identical systemic issue) - 15 cues total across al-data-modeling-review.md, al-testing-review.md, al-performance-review.md, al-web-services-review.md, and al-style-review.md. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> * Fix remaining correctness issues from Jesper's 2026-09-15 re-review - dimension-management-wiring: SaveDefaultDim's third argument is the shortcut dimension number (1-8), not the field's AL field ID; the fixture passed FieldNo(...) = 10. GetDefaultDimID's InheritFromDimSetID must be 0 when recomputing after the linking record changes, not the document's existing Dimension Set ID (which would retain the previous customer's leftover dimensions). Verified against DimensionManagement.Codeunit.al and BankDepositHeader.Table.al in the BCApps reference clone. - check-post-line-batch-pattern: "Post Line writes exactly one line to the ledger" overclaimed - Gen. Jnl.-Post Line alone calls InsertGLEntry from a dozen call sites (balancing entry, VAT, currency rounding, deferrals) and can write several G/L Entries per journal line. Reworded to "posts exactly one journal line" and softened the "distinct, non-overlapping responsibilities" absolute. - namespace-must-be-verified-from-source.bad.al: dropped the "resolves in a local build, fails in VS Code" comment (taught an inherent compiler/language-server disagreement that isn't real); reframed as stale/cached symbols, matching the prose fix already made. - file-datatype-saas.good.al: replaced the deprecated 5-argument UploadIntoStream overload with the current 2-argument one, and actually staged through TempBlob as the article's own Best Practice instructs (the declared TempBlob variable was previously unused). - test-data-must-be-random-and-complete: no longer treats a short-but-valid value as defective merely for being "underfilled" - AL field lengths are maxima, not minimums. Scoped to missing values or a scenario with an explicit length/format requirement (e.g. a truncation test). Updated the al-testing-review.md routing cue to match. - stored-derived-fields-must-not-be-exposed-directly: stopped mandating source-field exposure as part of the core pattern: the good fixture exposed only one of the derived value's two inputs (Hours Used, not Budgeted Hours), making the claimed "so the consumer can verify it" impossible. Reframed as an optional, all-or-nothing addition and fixed the fixture to expose both inputs. Rebased onto upstream/main to resolve conflicts in al-breaking-changes-review.md, al-data-modeling-review.md, al-performance-review.md, and al-style-review.md against merged PRs #148 and #153; all sides' worklist tokens/cues retained. * Fix remaining READ-convention sample links across this PR's 18 articles The same plain-backtick "See sample: \`x.good.al\`." form fixed on al-methods-limited-during-write-transactions (PR #161) turned up repo-wide on 15 more of this PR's articles - Knowledge-Retrieval.ps1 requires the markdown-link form to associate a sample with its article. All 16 fixed; the four local validators (frontmatter, knowledge-index, knowledge-retrieval, review-fixtures, skill-index) pass. * Fix two merge-critical correctness issues from Jesper's 2026-09-22 review - api-page-key-fields-must-be-editable-on-insert.good.al and stored-derived-fields-must-not-be-exposed-directly.good.al: both were writable API pages missing DelayedInsert = true, contradicting this repo's own api-page-delayedinsert-true rule - the canonical "good" samples were teaching code BCQuality itself flags. - dimension-management-wiring.good.al: UpdateDimensionSetID exited early when Customer.Get failed, leaving the previous customer's shortcut dimension and Dimension Set ID in place - the same staleness bug the InheritFromDimSetID = 0 fix (from the prior review round) was meant to prevent, just triggered by a failed lookup instead of a successful one. Now clears the shortcut field and recomputes with an empty source list on a failed lookup too, so GetDefaultDimID correctly returns an empty Dimension Set ID instead of never running. --------- Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
Michael Dieringer
GitHub
parent
07e324ddbc
commit
0a8c9a8556
56 changed files with 1144 additions and 3 deletions
13
microsoft/knowledge/appsource/file-datatype-saas.bad.al
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microsoft/knowledge/appsource/file-datatype-saas.bad.al
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codeunit 50104 "Import File Reader"
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{
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procedure ImportFile()
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var
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ImportFile: File;
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InStream: InStream;
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begin
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ImportFile.WriteMode(false);
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ImportFile.TextMode(true);
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ImportFile.Open('C:\Import\data.txt'); // fails in SaaS — no local filesystem
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ImportFile.CreateInStream(InStream);
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end;
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}
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24
microsoft/knowledge/appsource/file-datatype-saas.good.al
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microsoft/knowledge/appsource/file-datatype-saas.good.al
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codeunit 50104 "Import File Reader"
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{
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procedure ImportFile()
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var
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TempBlob: Codeunit "Temp Blob";
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FromInStream: InStream;
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ToOutStream: OutStream;
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InStream: InStream;
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begin
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if not UploadIntoStream('All Files (*.*)|*.*', FromInStream) then
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exit;
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TempBlob.CreateOutStream(ToOutStream);
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CopyStream(ToOutStream, FromInStream);
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TempBlob.CreateInStream(InStream);
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ParseStream(InStream);
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end;
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local procedure ParseStream(var InStream: InStream)
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begin
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// parse InStream content here
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end;
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}
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28
microsoft/knowledge/appsource/file-datatype-saas.md
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microsoft/knowledge/appsource/file-datatype-saas.md
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---
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bc-version: [all]
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domain: appsource
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keywords: [file-datatype, saas, onprem, uploadintostream, downloadfromstream, instream, outstream, streaming]
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technologies: [al]
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countries: [w1]
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application-area: [all]
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---
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# The File data type's direct I/O methods are OnPrem-only
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> Contributions welcome — open a PR to refine or extend this article.
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## Description
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The classic `File` variable type — `Open`/`Create`/`Read`/`Write`/`Close` against a path on the local or server filesystem — is scoped OnPrem-only. Code targeting Business Central Online that calls `File.Open`, `File.Create`, `File.Read`, or `File.Write` fails to compile against a Cloud-scoped project; it does not compile successfully and fail or get silently skipped at runtime. Separately, and regardless of the compile-time scoping, no server/local filesystem path is available to an extension actually running in Business Central Online.
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## Best Practice
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Use the stream-based equivalents: `UploadIntoStream` to read user-selected file content into an `InStream`, and `DownloadFromStream` to write an `OutStream`'s content to a file the user saves. Stage the content in a `TempBlob` between the stream and the rest of the parsing/formatting code.
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See sample: [`file-datatype-saas.good.al`](file-datatype-saas.good.al).
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## Anti Pattern
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Opening a hardcoded or user-supplied filesystem path with the `File` variable type. This is a strong signal the code was written for on-premises only, or copied from material that predates the cloud-first streaming APIs.
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See sample: [`file-datatype-saas.bad.al`](file-datatype-saas.bad.al).
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codeunit 50103 "Order Confirmation Notifier"
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{
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procedure Send(ToAddress: Text; Subject: Text; Body: Text)
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var
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Mail: Codeunit Mail;
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begin
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Mail.CreateMessage(ToAddress, '', '', Subject, Body, false, false);
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end;
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}
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codeunit 50103 "Order Confirmation Notifier"
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{
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procedure Send(ToAddress: Text; Subject: Text; Body: Text)
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var
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Email: Codeunit Email;
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EmailMessage: Codeunit "Email Message";
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begin
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EmailMessage.Create(ToAddress, Subject, Body, true);
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Email.Send(EmailMessage, Enum::"Email Scenario"::Default);
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end;
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}
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28
microsoft/knowledge/breaking-changes/prefer-email-module.md
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microsoft/knowledge/breaking-changes/prefer-email-module.md
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---
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bc-version: [all]
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domain: breaking-changes
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keywords: [email, codeunit-mail, email-message, email-scenario, email-account, smtp, sending-email]
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technologies: [al]
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countries: [w1]
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application-area: [all]
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---
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# Send email through the Email module, not Codeunit Mail (397)
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> Contributions welcome — open a PR to refine or extend this article.
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## Description
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Older AL code sends email by calling `Codeunit Mail (397)`. Business Central's current extensibility model is a different, richer object set — `Codeunit Email`, `Codeunit "Email Message"`, `enum "Email Scenario"`, and the `Email Account`/`Email Connector` interface (Microsoft 365, Current User, SMTP, or a custom connector). `Codeunit "Email Message"` is the in-memory object you build the message on; it is not itself the persisted Sent/Outbox/Draft record — that storage is managed separately once the message is queued or sent. New code built on `Codeunit Mail` inherits its SMTP-era, single-connector assumptions and leaves no Sent/Outbox trail behind.
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## Best Practice
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Build on `Codeunit Email` and `Codeunit "Email Message"`. Route the message through an `Email Scenario` so different document types can use different accounts without the calling code needing to know which account that is, and get a tracked Sent/Outbox/Draft record for free.
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See sample: [`prefer-email-module.good.al`](prefer-email-module.good.al).
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## Anti Pattern
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Calling `Codeunit Mail`'s `CreateMessage`. It still compiles and runs, but current `Codeunit Mail`'s own implementation of `CreateMessage` no longer sends anything by itself — it only raises integration events for a legacy subscriber to act on — so building new code on it means depending on whatever compatibility shim happens to still be wired up, with no first-class connector selection and no queryable Sent/Outbox/Draft record. `Send` and `GetErrorDesc` are not current members of `Codeunit Mail` at all; do not reference them.
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See sample: [`prefer-email-module.bad.al`](prefer-email-module.bad.al).
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codeunit 50101 "Meter Jnl.-Post"
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{
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procedure Post(var MeterJnlLine: Record "Meter Journal Line")
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var
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MeterLedgEntry: Record "Meter Ledger Entry";
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begin
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// Validation, Journal access, and posting all mixed in one routine.
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if not Confirm('Post journal lines?') then
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exit;
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if MeterJnlLine.FindSet() then
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repeat
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if MeterJnlLine.Quantity = 0 then
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Error('Quantity must not be zero.');
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MeterLedgEntry.Init();
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MeterLedgEntry.TransferFields(MeterJnlLine);
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MeterLedgEntry.Insert();
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MeterJnlLine.Delete();
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until MeterJnlLine.Next() = 0;
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end;
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}
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codeunit 50100 "Meter Jnl.-Check Line"
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{
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procedure CheckLine(var MeterJnlLine: Record "Meter Journal Line")
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begin
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// Reads setup/dimension data only, shows no UI beyond errors.
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if MeterJnlLine.Quantity = 0 then
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Error('Quantity must not be zero.');
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end;
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}
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codeunit 50101 "Meter Jnl.-Post Line"
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{
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procedure PostLine(var MeterJnlLine: Record "Meter Journal Line")
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var
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MeterLedgEntry: Record "Meter Ledger Entry";
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begin
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// Posts exactly one journal line; never touches the Journal table.
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MeterLedgEntry.Init();
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MeterLedgEntry.TransferFields(MeterJnlLine);
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MeterLedgEntry.Insert();
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end;
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}
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codeunit 50102 "Meter Jnl.-Post Batch"
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{
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procedure PostBatch(var MeterJnlLine: Record "Meter Journal Line")
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var
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CheckLine: Codeunit "Meter Jnl.-Check Line";
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PostLine: Codeunit "Meter Jnl.-Post Line";
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begin
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if MeterJnlLine.FindSet() then
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repeat
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CheckLine.CheckLine(MeterJnlLine);
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until MeterJnlLine.Next() = 0;
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if MeterJnlLine.FindSet() then
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repeat
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PostLine.PostLine(MeterJnlLine);
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MeterJnlLine.Delete();
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until MeterJnlLine.Next() = 0;
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end;
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}
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---
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bc-version: [all]
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domain: data-modeling
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keywords: [posting-routine, check-line, post-line, post-batch, companion-codeunit, yes-no-wrapper, journal]
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technologies: [al]
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countries: [w1]
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application-area: [all]
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---
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# Split posting routines into Check Line / Post Line / Post Batch
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> Contributions welcome — open a PR to refine or extend this article.
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## Description
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Business Central's own journal-based posting routines consistently follow a three-codeunit split, each with one primary responsibility — `Codeunit "Gen. Jnl.-Check Line"` / `"Gen. Jnl.-Post Line"` / `"Gen. Jnl.-Post Batch"` for the general journal, and the same `<Journal>-Check Line` / `<Journal>-Post Line` / `<Journal>-Post Batch` shape repeated for Item, Resource, Job, Fixed Asset, Insurance, and Cost Accounting journals: `Check Line` validates one line, `Post Line` posts exactly one journal line — `Gen. Jnl.-Post Line` itself can write more than one G/L Entry per call (a balancing entry, VAT, currency rounding, deferrals), so "exactly one line" describes its input, not a one-entry-out guarantee — and `Post Batch` loops both across the journal. A document posting routine (posting one document at a time) calls `Post Line` directly and skips `Post Batch`. This is the standard shape to evaluate a new journal-based posting routine against, not a platform-enforced constraint — a routine with a genuinely different transaction/reuse shape may legitimately organize itself differently, and the three codeunits' responsibilities are a useful default split, not a guarantee that every implementation keeps them non-overlapping. But a new routine that blurs this split without a specific reason either misses functionality other code expects to call directly, or exposes an interaction surface it shouldn't.
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## Best Practice
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`Check Line` reads setup/dimension data only on its first call and shows no UI beyond errors. `Post Line` only operates on the record passed to it — never the Journal table — so it can be called directly by other posting code, including a document posting routine. `Post Batch` is the only one of the three that reads and updates the Journal table, and it is the only one invoked from the Post action on a journal page. A `-Post` document codeunit is never called directly from a page; a page calls a `-Post (Yes/No)` confirmation wrapper instead, so the same `-Post` codeunit can also run unattended from a batch-posting report.
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See sample: [`check-post-line-batch-pattern.good.al`](check-post-line-batch-pattern.good.al).
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## Anti Pattern
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A single monolithic posting codeunit that reads the Journal table, validates lines, writes ledger entries, and shows confirmation dialogs all in one procedure. It cannot be reused by another posting routine without fabricating journal records, and it cannot run unattended because it insists on user interaction.
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See sample: [`check-post-line-batch-pattern.bad.al`](check-post-line-batch-pattern.bad.al).
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table 50100 "Course"
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{
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fields
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{
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field(1; "No."; Code[20]) { }
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field(10; "Global Dimension 1 Code"; Code[20])
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{
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// No CaptionClass, no OnValidate call into DimensionManagement.
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// Accepts any value; never becomes a Default Dimension record.
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TableRelation = "Dimension Value".Code;
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}
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}
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}
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// Master data: Default Dimension records, no Dimension Set ID field.
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table 50100 "Course"
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{
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fields
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{
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field(1; "No."; Code[20]) { }
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field(10; "Global Dimension 1 Code"; Code[20])
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{
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CaptionClass = '1,1,1';
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TableRelation = "Dimension Value".Code where(
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"Global Dimension No." = const(1), Blocked = const(false));
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trigger OnValidate()
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var
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DimMgt: Codeunit DimensionManagement;
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begin
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DimMgt.ValidateDimValueCode(1, "Global Dimension 1 Code");
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DimMgt.SaveDefaultDim(Database::Course, "No.", 1, "Global Dimension 1 Code");
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end;
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}
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}
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trigger OnDelete()
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var
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DimMgt: Codeunit DimensionManagement;
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begin
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DimMgt.DeleteDefaultDim(Database::Course, "No.");
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end;
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}
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// Transactional/document data: a single Dimension Set ID, inherited from the
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// related master record and overridable via shortcut dimension fields.
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table 50101 "Course Registration Header"
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{
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fields
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{
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field(1; "No."; Code[20]) { }
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field(2; "Customer No."; Code[20])
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{
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TableRelation = Customer;
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trigger OnValidate()
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begin
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UpdateDimensionSetID();
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end;
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}
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field(10; "Shortcut Dimension 1 Code"; Code[20])
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{
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CaptionClass = '1,1,1';
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TableRelation = "Dimension Value".Code where(
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"Global Dimension No." = const(1), Blocked = const(false));
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trigger OnValidate()
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var
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DimMgt: Codeunit DimensionManagement;
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begin
|
||||
DimMgt.ValidateShortcutDimValues(1, "Shortcut Dimension 1 Code", "Dimension Set ID");
|
||||
end;
|
||||
}
|
||||
field(480; "Dimension Set ID"; Integer)
|
||||
{
|
||||
Editable = false;
|
||||
TableRelation = "Dimension Set Entry"."Dimension Set ID";
|
||||
}
|
||||
}
|
||||
|
||||
local procedure UpdateDimensionSetID()
|
||||
var
|
||||
Customer: Record Customer;
|
||||
DimMgt: Codeunit DimensionManagement;
|
||||
DefaultDimSource: List of [Dictionary of [Integer, Code[20]]];
|
||||
GlobalDim2Code: Code[20];
|
||||
begin
|
||||
// Recompute from scratch (InheritFromDimSetID = 0) whether or not the
|
||||
// customer lookup succeeds. Passing the existing "Dimension Set ID"
|
||||
// here would inherit dimensions from whichever record the document
|
||||
// was previously linked to, and exiting early on a failed Get would
|
||||
// leave that same stale data in place — both defeat the point of
|
||||
// this procedure. Clearing the shortcut field and recomputing with
|
||||
// an empty source list (when the customer doesn't exist) correctly
|
||||
// clears the document's dimensions instead of leaving old ones.
|
||||
"Shortcut Dimension 1 Code" := '';
|
||||
if Customer.Get("Customer No.") then
|
||||
DimMgt.AddDimSource(DefaultDimSource, Database::Customer, "Customer No.");
|
||||
"Dimension Set ID" :=
|
||||
DimMgt.GetDefaultDimID(
|
||||
DefaultDimSource, '', "Shortcut Dimension 1 Code", GlobalDim2Code, 0, 0);
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,35 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: data-modeling
|
||||
keywords: [dimensions, dimensionmanagement, global-dimension, shortcut-dimension, default-dimension, validatedimvaluecode, getdefaultdimid]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Wire dimension support through DimensionManagement, not ad hoc fields
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
Adding dimension support to a custom table is not just a matter of adding a `Code[20]` field, and master tables and document/transactional tables wire into `Codeunit "Dimension Management"` through two different models — treating them as one mechanism is itself the mistake this article corrects:
|
||||
|
||||
- **Master data** (a custom master table, e.g. "Course") persists **Default Dimension** records: each shortcut dimension field validates through `ValidateDimValueCode`, then the result is saved via `SaveDefaultDim`, and `DeleteDefaultDim` removes them again in `OnDelete`. Both `ValidateDimValueCode` and `SaveDefaultDim` take the shortcut dimension *number* (1-8, matching `General Ledger Setup`'s "Shortcut Dimension N Code" fields) as their first/third argument respectively — not the AL field ID of the table field being validated. The master record itself carries no `Dimension Set ID` field.
|
||||
- **Transactional/document data** (a custom document or journal-line table) carries a single **`Dimension Set ID`** field — a pointer to a shared, deduplicated set of dimension values in `Dimension Set Entry`, assembled from whatever the document inherited plus whatever the user overrode. A document does not acquire that ID by calling `SaveDefaultDim`; it builds a source list with `AddDimSource` (naming the related master table and its key, e.g. `Database::Customer`), then calls `GetDefaultDimID` to compute a new `Dimension Set ID` that inherits the master's Default Dimension records. Editing a shortcut dimension field directly on the document validates through `ValidateShortcutDimValues`, which updates the same `Dimension Set ID` in place rather than writing a separate Default Dimension record.
|
||||
|
||||
Skipping the model that actually matches the table's kind produces a field that looks correct in the designer but silently fails to save, validate, or carry through to postings — or, for a document, one that never picks up the customer's/vendor's own dimensions at all.
|
||||
|
||||
## Best Practice
|
||||
|
||||
For a master table, validate each shortcut dimension field through `ValidateDimValueCode`, save the result with `SaveDefaultDim`, and delete the matching Default Dimension records in `OnDelete`.
|
||||
|
||||
For a document table, when the field that attaches the document to a master record changes (e.g. `Customer No.`), call `AddDimSource` naming that master table and key, then `GetDefaultDimID` to compute the document's new `Dimension Set ID`, inheriting the master's Default Dimension records. Pass `0` for `GetDefaultDimID`'s `InheritFromDimSetID` argument in this case — passing the document's *existing* `Dimension Set ID` instead inherits whatever dimensions were already in it, so a value the previous linked record supplied can survive into the new one even where the new record has no default for that dimension. Run this same recompute — clear the shortcut field, call `GetDefaultDimID` with no source added — when the lookup on the new key fails (blank or an invalid value), too: exiting early instead leaves the previous record's dimensions in place, which is the same staleness bug the `InheritFromDimSetID = 0` rule exists to prevent. Validate the document's own Shortcut Dimension fields through `ValidateShortcutDimValues`, which updates that same `Dimension Set ID` in place rather than persisting a separate Default Dimension record.
|
||||
|
||||
See sample: [`dimension-management-wiring.good.al`](dimension-management-wiring.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Adding a dimension-looking field with only a `TableRelation` to Dimension Value, and no call into `DimensionManagement` at all. The field accepts input but never becomes a real Default Dimension record, so it does not validate against blocked values and does not flow into postings.
|
||||
|
||||
See sample: [`dimension-management-wiring.bad.al`](dimension-management-wiring.bad.al).
|
||||
|
|
@ -0,0 +1,14 @@
|
|||
table 50100 "Period Stats"
|
||||
{
|
||||
fields
|
||||
{
|
||||
field(1; "Period Start"; Date) { }
|
||||
field(2; Flow; Enum "Some Flow") { }
|
||||
}
|
||||
keys
|
||||
{
|
||||
// Table already shipped with key(PK; "Period Start").
|
||||
// Adding Flow here breaks every upgrade with AS0009.
|
||||
key(PK; Flow, "Period Start") { Clustered = true; }
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,24 @@
|
|||
table 50100 "Period Stats"
|
||||
{
|
||||
fields
|
||||
{
|
||||
field(1; "Period Start"; Date) { }
|
||||
}
|
||||
keys
|
||||
{
|
||||
key(PK; "Period Start") { Clustered = true; }
|
||||
}
|
||||
}
|
||||
|
||||
table 50101 "Period Stats By Flow"
|
||||
{
|
||||
fields
|
||||
{
|
||||
field(1; "Period Start"; Date) { }
|
||||
field(2; Flow; Enum "Some Flow") { }
|
||||
}
|
||||
keys
|
||||
{
|
||||
key(PK; Flow, "Period Start") { Clustered = true; }
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: data-modeling
|
||||
keywords: [primary-key, clustered-key, table-design, appsource, breaking-change, schema-upgrade]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Never Change a Published Table's Primary or Clustered Key Field List
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
Once a table has shipped — to AppSource, or to any customer environment that has already upgraded onto it — its primary key, and any other key marked `Clustered = true`, is frozen. This includes adding a field to the key, not only removing or reordering one: Business Central identifies existing rows by their key value, so any change to which fields compose that key invalidates every row already stored under the old shape, and the platform's upgrade validation rejects it outright (`AS0009`). This is easy to trip over because it doesn't look like the well-known "don't delete a field" mistake — the field being added is often brand new, and folding a new discriminating dimension straight into the existing key feels like the natural, un-denormalized way to model it. On an unpublished table that is correct; on a published one it is a breaking schema change regardless of which direction the field list changed, and there is no in-place fix once the upgrade is rejected, only reverting the key to its published shape.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Leave a published table's key exactly as shipped. Model a new discriminating dimension as a separate table with its own key instead of adding a field to the existing key, and branch orchestration code by the new dimension rather than filtering one shared table on an extra key field.
|
||||
|
||||
See sample: [`do-not-change-primary-key.good.al`](do-not-change-primary-key.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Adding a field to a published table's primary or clustered key to distinguish a new case. This fails AppSource validation or any customer upgrade with `AS0009` as soon as rows already exist under the old key shape, whether the field is being added, removed, or reordered.
|
||||
|
||||
See sample: [`do-not-change-primary-key.bad.al`](do-not-change-primary-key.bad.al).
|
||||
|
|
@ -0,0 +1,12 @@
|
|||
codeunit 50100 "Tax Posting Helper"
|
||||
{
|
||||
procedure GetTaxAccount(var Setup: Record "Sales & Receivables Setup"): Code[20]
|
||||
var
|
||||
DefaultTaxAccountTxt: Label 'DEFAULT-TAX';
|
||||
begin
|
||||
Setup.Get();
|
||||
if Setup."Tax Account No." <> '' then
|
||||
exit(Setup."Tax Account No.");
|
||||
exit(DefaultTaxAccountTxt);
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,9 @@
|
|||
codeunit 50100 "Tax Posting Helper"
|
||||
{
|
||||
procedure GetTaxAccount(var Setup: Record "Sales & Receivables Setup"): Code[20]
|
||||
begin
|
||||
Setup.Get();
|
||||
Setup.TestField("Tax Account No.");
|
||||
exit(Setup."Tax Account No.");
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: data-modeling
|
||||
keywords: [testfield, setup-table, configuration, mandatory-field, silent-fallback, correctness]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# TestField a Setup-Table Value Before Using It in a Correctness-Critical Branch
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
A procedure that reads a field from a setup or configuration table inside a branch where the surrounding logic has already decided that value is required needs to guard against it being blank. A common anti-pattern silently treats "blank" as "feature not wanted": it checks the field for emptiness and falls through to a default instead of raising an error. `Get()` succeeding on the setup record only proves the record exists, not that the specific field was ever configured, so the fallback path makes a missing configuration indistinguishable from a deliberate one — and the wrong outcome, especially in financial, tax, or compliance postings, surfaces silently rather than as a crash a tester would notice.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Once a business rule has decided that a setup-table field's value is required for a branch to behave correctly, call `TestField` on it before use, even though a plain read would "work" by returning a blank or zero without erroring. Write a test that blanks the setup field and asserts the resulting error, so the guard itself is verified rather than merely present.
|
||||
|
||||
See sample: [`testfield-required-setup-field.good.al`](testfield-required-setup-field.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Reading a required setup-table field behind a presence check that falls through to a default value instead of erroring. This looks defensive because it never crashes, but it converts "administrator forgot to configure this" into "system silently did something else" — worse than a hard failure, because nobody is told anything went wrong.
|
||||
|
||||
See sample: [`testfield-required-setup-field.bad.al`](testfield-required-setup-field.bad.al).
|
||||
|
|
@ -0,0 +1,16 @@
|
|||
report 50105 "Sales Quote Confirmation"
|
||||
{
|
||||
UsageCategory = Documents;
|
||||
ApplicationArea = All;
|
||||
|
||||
rendering
|
||||
{
|
||||
layout(RDLC)
|
||||
{
|
||||
Type = RDLC;
|
||||
LayoutFile = './Layouts/SalesQuoteConfirmation.rdl';
|
||||
}
|
||||
}
|
||||
|
||||
DefaultRenderingLayout = RDLC;
|
||||
}
|
||||
|
|
@ -0,0 +1,17 @@
|
|||
report 50105 "Sales Quote Confirmation"
|
||||
{
|
||||
UsageCategory = Documents;
|
||||
ApplicationArea = All;
|
||||
|
||||
rendering
|
||||
{
|
||||
layout(Word)
|
||||
{
|
||||
Type = Word;
|
||||
LayoutFile = './Layouts/SalesQuoteConfirmation.docx';
|
||||
Caption = 'Word Layout';
|
||||
}
|
||||
}
|
||||
|
||||
DefaultRenderingLayout = Word;
|
||||
}
|
||||
|
|
@ -0,0 +1,34 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: performance
|
||||
keywords: [report-layout, word-layout, rdlc, document-report, sandbox-app-domain, rendering]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Document reports should default to a Word layout, not RDLC
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
For a document report — an invoice, statement, order confirmation, or any report meant to be printed, emailed, or exported as a single-record document — Microsoft's own guidance recommends a `Word` rendering layout over `RDLC`: "RDL layouts can result in slower performance with document reports, regarding actions that are related to the user interface (for example, like sending emails) compared to Word layouts," and "we recommend that you design Word layouts instead of RDL" for this report shape (see Sources). This is a documented recommendation, not a universal guarantee that Word outperforms RDLC for every workload, and it does not apply to every report: tabular/list reports with heavy aggregation or calculated columns are still often a better fit for RDLC or Excel.
|
||||
|
||||
## Best Practice
|
||||
|
||||
For document reports, prefer a `Word` layout (`DefaultRenderingLayout = Word`) over RDLC unless specific layout requirements favor RDLC. Reserve RDLC (or Excel) for reports that represent a data listing rather than a document.
|
||||
|
||||
## Sources
|
||||
|
||||
- [Report Design Overview](https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-report-design-overview)
|
||||
- [Creating an RDL layout report](https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-report-performance)
|
||||
- [Troubleshooting reports / Report performance](https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-reports-troubleshooting)
|
||||
|
||||
See sample: [`document-report-word-layout.good.al`](document-report-word-layout.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Defaulting a document report's layout to RDLC out of habit or because a template happened to use it. This inherits RDLC's sandboxed-app-domain performance cost with no benefit tied to the report's actual content or calculation needs.
|
||||
|
||||
See sample: [`document-report-word-layout.bad.al`](document-report-word-layout.bad.al).
|
||||
|
|
@ -0,0 +1,24 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: style
|
||||
keywords: [build, output, alpackages, artifact-hygiene, outfolder, project-root]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Write AL Build Artifacts to an Intentional Output Location
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
An AL project's compiled `.app` file can be written to the project root by default, and current tooling explicitly supports choosing a different destination instead — `ALTool`'s `--outfolder` option and the `al_build` agent tool's `outputPath` parameter both exist for this. The problem this rule addresses is not that root-level output is technically invalid; it is agents leaving generated `.app` files scattered through arbitrary source locations, or treating a compiled artefact as if it were part of the source tree (committing it, editing around it, referencing it as a dependency by hand).
|
||||
|
||||
## Best Practice
|
||||
|
||||
Write build artifacts to a deliberate, dedicated output location — configured via the build tool actually in use (e.g. `ALTool --outfolder`, or an explicit `outputPath` on the agent build tool) — and add that folder to `.gitignore`. Treat a compiled `.app` as a build artifact, never as a source file to commit or hand-edit around.
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Letting `.app` files accumulate in arbitrary or unversioned locations without a deliberate output path, or committing compiled artefacts into source control alongside the AL files that produced them.
|
||||
11
microsoft/knowledge/style/al-identifiers-english.bad.al
Normal file
11
microsoft/knowledge/style/al-identifiers-english.bad.al
Normal file
|
|
@ -0,0 +1,11 @@
|
|||
codeunit 50100 "Sales Amount Calculator"
|
||||
{
|
||||
procedure BeregnTotalbeloeb(var Salgslinje: Record "Sales Line"): Decimal
|
||||
var
|
||||
Beloeb: Decimal;
|
||||
begin
|
||||
Salgslinje.CalcSums(Amount);
|
||||
Beloeb := Salgslinje.Amount;
|
||||
exit(Beloeb);
|
||||
end;
|
||||
}
|
||||
11
microsoft/knowledge/style/al-identifiers-english.good.al
Normal file
11
microsoft/knowledge/style/al-identifiers-english.good.al
Normal file
|
|
@ -0,0 +1,11 @@
|
|||
codeunit 50100 "Sales Amount Calculator"
|
||||
{
|
||||
procedure CalculateTotalAmount(var SalesLine: Record "Sales Line"): Decimal
|
||||
var
|
||||
TotalAmount: Decimal;
|
||||
begin
|
||||
SalesLine.CalcSums(Amount);
|
||||
TotalAmount := SalesLine.Amount;
|
||||
exit(TotalAmount);
|
||||
end;
|
||||
}
|
||||
28
microsoft/knowledge/style/al-identifiers-english.md
Normal file
28
microsoft/knowledge/style/al-identifiers-english.md
Normal file
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: style
|
||||
keywords: [identifiers, naming, english, captions, translation]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Write AL Identifiers in English Only
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
All AL identifiers — variables, procedures, parameters, fields, object names, enum values, and label identifiers — must be written in English, regardless of the developer's native language. Translations are handled separately through captions, tooltips, and XLIFF files, never by writing Danish, German, or other non-English identifiers directly into AL source code. This is not a stylistic preference: the public `microsoft/BCApps` codebase, maintained by engineers of many nationalities across hundreds of thousands of lines of AL, uses exclusively English identifiers, with all localization handled via caption properties and XLIFF rather than by changing identifier names. On any multi-contributor codebase, non-English identifiers make the code unreadable to contributors who don't share that language.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Write every identifier in English, and translate developer intent rather than transliterating it — when a requirement is described in another language, the resulting variable, procedure, and field names should still read as English. Captions and tooltips may carry target-language text in the source file, with locale translations managed through XLIFF.
|
||||
|
||||
See sample: [`al-identifiers-english.good.al`](al-identifiers-english.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Using native-language identifiers such as a Danish variable or procedure name in AL source code, relying on the fact that the code still compiles and runs correctly. This makes the code unreadable to non-native-language contributors and mixes localization concerns into source that should stay language-neutral.
|
||||
|
||||
See sample: [`al-identifiers-english.bad.al`](al-identifiers-english.bad.al).
|
||||
|
|
@ -0,0 +1,22 @@
|
|||
table 50100 "Sales Task"
|
||||
{
|
||||
fields
|
||||
{
|
||||
field(1; "No."; Code[20]) { }
|
||||
field(10; Status; Option)
|
||||
{
|
||||
OptionMembers = Active,Blocked;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
codeunit 50100 "Sales Task Check"
|
||||
{
|
||||
procedure IsOverdue(DueDate: Date): Integer
|
||||
begin
|
||||
// 0 = No, 1 = Yes
|
||||
if DueDate < Today then
|
||||
exit(1);
|
||||
exit(0);
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,16 @@
|
|||
table 50100 "Sales Task"
|
||||
{
|
||||
fields
|
||||
{
|
||||
field(1; "No."; Code[20]) { }
|
||||
field(10; Blocked; Boolean) { }
|
||||
}
|
||||
}
|
||||
|
||||
codeunit 50100 "Sales Task Check"
|
||||
{
|
||||
procedure IsOverdue(DueDate: Date): Boolean
|
||||
begin
|
||||
exit(DueDate < Today);
|
||||
end;
|
||||
}
|
||||
28
microsoft/knowledge/style/binary-choice-must-be-boolean.md
Normal file
28
microsoft/knowledge/style/binary-choice-must-be-boolean.md
Normal file
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: style
|
||||
keywords: [boolean, option, yes-no, magic-number, variable-typing, field-typing]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Binary yes/no choices must be typed as Boolean, not Option or Integer
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
When a field or variable represents a genuine true/false state — yes/no, on/off, active/inactive, blocked/not blocked — it should be typed `Boolean`. Modeling that same predicate as an `Option`/`Enum` with two members, or as an `Integer` with two magic-number values, adds a layer of indirection a reader has to resolve before understanding the code. This is about semantics, not member count: a domain concept that currently has exactly two named alternatives — Inbound/Outbound, Debit/Credit, Buy/Sell — is not automatically a Boolean in disguise. An `Enum` can be the clearer model there, including when it needs to implement an interface, preserve an existing contract, or leave room for a future third value. The distinction is whether the domain is genuinely a stable predicate, not how many states it currently has.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Type a field or variable as `Boolean` when the domain concept is inherently a true/false state. Do not replace a meaningful two-option domain model with a Boolean solely because it currently has two values.
|
||||
|
||||
See sample: [`binary-choice-must-be-boolean.good.al`](binary-choice-must-be-boolean.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Modeling a yes/no choice as an `Option` with two members, or as an `Integer` with magic-number values, forces every caller to remember which value means what and leaves room for a meaningless third value.
|
||||
|
||||
See sample: [`binary-choice-must-be-boolean.bad.al`](binary-choice-must-be-boolean.bad.al).
|
||||
|
|
@ -0,0 +1,22 @@
|
|||
table 50101 "Course"
|
||||
{
|
||||
fields
|
||||
{
|
||||
field(1; "No."; Code[20]) { }
|
||||
// 1 = Beginner, 2..3 = Intermediate, 4+ = Advanced
|
||||
field(10; Difficulty; Integer) { }
|
||||
}
|
||||
}
|
||||
|
||||
codeunit 50100 "Course Level Helper"
|
||||
{
|
||||
procedure LevelText(Difficulty: Integer): Text
|
||||
begin
|
||||
case Difficulty of
|
||||
1:
|
||||
exit('Beginner');
|
||||
2, 3:
|
||||
exit('Intermediate');
|
||||
end;
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,17 @@
|
|||
enum 50100 "Course Difficulty"
|
||||
{
|
||||
Extensible = true;
|
||||
|
||||
value(0; Beginner) { }
|
||||
value(1; Intermediate) { }
|
||||
value(2; Advanced) { }
|
||||
}
|
||||
|
||||
table 50101 "Course"
|
||||
{
|
||||
fields
|
||||
{
|
||||
field(1; "No."; Code[20]) { }
|
||||
field(10; Difficulty; Enum "Course Difficulty") { }
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: style
|
||||
keywords: [enum, option, integer, magic-number, variable-typing, field-typing]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# A fixed set of named choices must use Enum, not a raw Integer
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
When a variable or field represents a fixed set of named, mutually exclusive states — a difficulty level, a document type, a processing status — it should be typed as `Enum` (or `Option` when extending an object that still uses the legacy type). Representing that same state as a plain `Integer` and tracking the meaning of each value in a comment or in a developer's head is a magic-number anti-pattern: the compiler cannot catch an out-of-range value, and branches read as opaque numbers instead of names. This is about semantics, not member count, matching `binary-choice-must-be-boolean.md`'s own distinction: a domain concept that is genuinely a stable true/false predicate belongs in `Boolean` even if someone represents it as a two-value `Enum`, while a domain concept with exactly two current named states is not automatically a Boolean in disguise — it stays an `Enum` when the states are named alternatives rather than a yes/no flag, or when it needs to implement an interface, preserve an existing contract, or leave room for a future third value.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Declare an `Enum` with named values and branch on the enum value, not a raw number.
|
||||
|
||||
See sample: [`fixed-choice-set-must-use-enum-not-integer.good.al`](fixed-choice-set-must-use-enum-not-integer.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Using a plain `Integer` field with the meaning of each value tracked only in a comment pushes the documentation of the states into something the compiler cannot check and a future maintainer cannot rely on.
|
||||
|
||||
See sample: [`fixed-choice-set-must-use-enum-not-integer.bad.al`](fixed-choice-set-must-use-enum-not-integer.bad.al).
|
||||
|
|
@ -0,0 +1,12 @@
|
|||
codeunit 50100 "Sales Task Notify"
|
||||
{
|
||||
procedure NotifyUpdate(Count: Integer; CustomerNo: Code[20])
|
||||
begin
|
||||
MESSAGE('%1 records updated.', Count);
|
||||
|
||||
IF NOT CONFIRM('Delete %1?', FALSE, CustomerNo) THEN
|
||||
EXIT;
|
||||
|
||||
ERROR(STRSUBSTNO('%1 must not be blank.', CustomerNo));
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,12 @@
|
|||
codeunit 50100 "Sales Task Notify"
|
||||
{
|
||||
procedure NotifyUpdate(Count: Integer; CustomerNo: Code[20])
|
||||
begin
|
||||
Message('%1 records updated.', Count);
|
||||
|
||||
if not Confirm('Delete %1?', false, CustomerNo) then
|
||||
exit;
|
||||
|
||||
Error(StrSubstNo('%1 must not be blank.', CustomerNo));
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: style
|
||||
keywords: [casing, intrinsic-function, built-in-function, message, error, confirm, strsubstno, legacy, c-al, pascalcase]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Intrinsic AL function calls use modern casing, not legacy ALL-CAPS
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
AL is case-insensitive, so `MESSAGE(...)`, `ERROR(...)`, `CONFIRM(...)`, and `STRSUBSTNO(...)` compile and run identically to `Message(...)`, `Error(...)`, `Confirm(...)`, and `StrSubstNo(...)`. Modern AL — Microsoft's own current samples and current reference codebases — writes intrinsic/built-in function calls in the casing Microsoft assigns to the function's declared name, typically PascalCase. This is a codebase-convention claim, not a claim about what the VS Code formatter enforces: the formatter normalizes particular syntax but is not a mechanism for recasing every intrinsic function call, so do not cite formatter behavior as the reason to follow this convention. ALL-CAPS calls are a holdover from classic C/AL and signal code that has not been modernized, even though it compiles and runs correctly. Reserved keywords such as `if`, `begin`, and `for` are a separate, already-tooled concern; intrinsic function names are identifiers, not keywords, so that tooling does not catch ALL-CAPS intrinsic function calls.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Call intrinsic functions in their modern, PascalCase form.
|
||||
|
||||
See sample: [`intrinsic-al-functions-must-use-modern-casing.good.al`](intrinsic-al-functions-must-use-modern-casing.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
ALL-CAPS intrinsic function calls trip no compiler error, but they are a reliable signal that a code block was copied from old C/AL material or outdated training content rather than written against current AL conventions.
|
||||
|
||||
See sample: [`intrinsic-al-functions-must-use-modern-casing.bad.al`](intrinsic-al-functions-must-use-modern-casing.bad.al).
|
||||
|
|
@ -0,0 +1,13 @@
|
|||
namespace Contoso.Extensions;
|
||||
|
||||
using System.Performance; // guessed; never verified against the source file
|
||||
|
||||
codeunit 50100 "Tooling Extension"
|
||||
{
|
||||
procedure Run()
|
||||
var
|
||||
ToolingPage: Page "Some Tooling Page"; // guessed namespace; can still resolve against a stale or cached symbol package, then fail once checked against the object's current source or a freshly downloaded one
|
||||
begin
|
||||
ToolingPage.Run();
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,16 @@
|
|||
// Verified by reading line 1 of the source file for "Some Tooling Page":
|
||||
// namespace System.Tooling;
|
||||
|
||||
namespace Contoso.Extensions;
|
||||
|
||||
using System.Tooling;
|
||||
|
||||
codeunit 50100 "Tooling Extension"
|
||||
{
|
||||
procedure Run()
|
||||
var
|
||||
ToolingPage: Page "Some Tooling Page";
|
||||
begin
|
||||
ToolingPage.Run();
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: style
|
||||
keywords: [namespace, verification, source-of-truth, using-statement]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Resolve a namespace from the referenced object's source or symbols, never by guessing
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
Since Business Central 2024 release wave 1, Microsoft's own objects are organized under a deep `Microsoft.*` namespace tree that has been renamed and restructured repeatedly. When adding a `using` directive for an existing AL object (table, codeunit, page, enum, interface, etc.), guessing its namespace from the object's name, from an older codebase, or from general familiarity produces a statement that can look plausible and still resolve to the wrong object, or fail to resolve at all, once checked against the object's actual current namespace. The reliable sources are the object's own source file (its `namespace` declaration) or, for a dependency without accessible source, its AL symbol package — not the object's name or a remembered convention.
|
||||
|
||||
## Best Practice
|
||||
|
||||
When referencing an existing AL object, resolve its namespace from that object's actual source file or symbol definition — never infer or invent one from its name, functional area, or naming convention.
|
||||
|
||||
See sample: [`namespace-must-be-verified-from-source.good.al`](namespace-must-be-verified-from-source.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Writing a `using` statement from memory, from an incomplete path, or from a plausible-looking guess. It can appear correct while actually resolving to the wrong object, or fail to resolve, once checked against stale or mismatched symbols, a different build configuration, or the object's actual current source — not because the compiler and the AL Language Server apply different namespace-resolution rules; they don't.
|
||||
|
||||
See sample: [`namespace-must-be-verified-from-source.bad.al`](namespace-must-be-verified-from-source.bad.al).
|
||||
|
|
@ -0,0 +1,15 @@
|
|||
codeunit 50100 "Customer Lookup"
|
||||
{
|
||||
procedure GetCustomerName(CustomerNo: Code[20]; var Name: Text[100])
|
||||
var
|
||||
Customer: Record Customer;
|
||||
begin
|
||||
if Customer.Get(CustomerNo) then
|
||||
Name := Customer.Name;
|
||||
end;
|
||||
|
||||
procedure Sample()
|
||||
begin
|
||||
GetCustomerName('10000', 'placeholder'); // compile error: literal is not addressable
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,17 @@
|
|||
codeunit 50100 "Customer Lookup"
|
||||
{
|
||||
procedure GetCustomerName(CustomerNo: Code[20]; var Name: Text[100])
|
||||
var
|
||||
Customer: Record Customer;
|
||||
begin
|
||||
if Customer.Get(CustomerNo) then
|
||||
Name := Customer.Name;
|
||||
end;
|
||||
|
||||
procedure Sample()
|
||||
var
|
||||
CustName: Text[100];
|
||||
begin
|
||||
GetCustomerName('10000', CustName);
|
||||
end;
|
||||
}
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: style
|
||||
keywords: [var-parameter, by-reference, pass-by-reference, literal, constant, compile-error, procedure-call]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# A `var` parameter must be called with a variable, never a literal or expression
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
When a procedure declares a parameter with `var`, that parameter is passed by reference: the callee writes back into the caller's own memory location. This means the argument at the call site must be an actual variable, something with an address. A string literal, a numeric constant, or a computed expression has no address to write back to, so passing one to a `var` parameter fails to compile. Before writing a call, check the callee's signature for `var` on each parameter position being supplied a literal or expression — if present, a variable declared in the caller's own scope must be used instead.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Declare a variable in the caller's scope and pass it to the `var` parameter.
|
||||
|
||||
See sample: [`var-parameters-require-an-addressable-variable.good.al`](var-parameters-require-an-addressable-variable.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Passing a literal or a computed expression to a `var` parameter position fails to compile, because neither has an address the callee can write back to.
|
||||
|
||||
See sample: [`var-parameters-require-an-addressable-variable.bad.al`](var-parameters-require-an-addressable-variable.bad.al).
|
||||
|
|
@ -0,0 +1,14 @@
|
|||
[Test]
|
||||
procedure PostsSalesOrderForCashCustomer()
|
||||
var
|
||||
Customer: Record Customer;
|
||||
SalesHeader: Record "Sales Header";
|
||||
begin
|
||||
// Assumes a 'CASH' customer already exists in the environment —
|
||||
// fails on any database where it doesn't.
|
||||
Customer.Get('CASH');
|
||||
LibrarySales.CreateSalesHeader(
|
||||
SalesHeader, SalesHeader."Document Type"::Order, Customer."No.");
|
||||
|
||||
// ... add lines, post, assert ...
|
||||
end;
|
||||
|
|
@ -0,0 +1,13 @@
|
|||
[Test]
|
||||
procedure PostsSalesOrderForRandomCustomer()
|
||||
var
|
||||
Customer: Record Customer;
|
||||
SalesHeader: Record "Sales Header";
|
||||
begin
|
||||
// Freshly created customer, owned by this test — no assumption about what exists.
|
||||
LibrarySales.CreateCustomer(Customer);
|
||||
LibrarySales.CreateSalesHeader(
|
||||
SalesHeader, SalesHeader."Document Type"::Order, Customer."No.");
|
||||
|
||||
// ... add lines, post, assert ...
|
||||
end;
|
||||
|
|
@ -0,0 +1,30 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: testing
|
||||
keywords: [testing, test-data, random, library, any]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Generate Test Data Programmatically, Never Assume Existing Records
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
A BC test company normally contains initialized system/setup data — an AL test suite should not assume an empty database, but it must be independent of unrelated business records: create the records and setup it owns rather than looking up a specific code, number, or name assumed to already exist, since that makes the test fail for reasons unrelated to the code under test. Every mandatory field on a created record also needs an actual value — leaving one blank because setup-time validation happens to allow it produces a record that doesn't reflect a real one and can fail later, elsewhere in the flow (posting, a report, a later assertion), for a reason unrelated to what the test claims to check. A short-but-valid value is not itself a defect: AL field lengths are maxima, not minimums, so a two-character value in a `Text[100]` field is fine unless the scenario specifically depends on the field's length or shape — for example, a test that verifies truncation or a format check needs a value chosen to exercise that boundary, not an arbitrary short one.
|
||||
|
||||
Not every value should be generated, though. Incidental fixture data — identifiers, names, descriptions — should generally come from the standard library codeunits rather than be tied to specific existing data. But values that materially define the scenario under test — amounts, quantities, percentages, dates, thresholds, rounding precision — should stay explicit and deliberately chosen, not randomized: a rounding test needs values placed deliberately around the rounding boundary, not a random one that might miss it entirely.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Use the standard library codeunits (`Library - ERM`, `Library - Inventory`, `Library - Sales`, `Library - Utility`) to generate incidental fixture values — they produce valid, unique-enough data via number series and controlled randomness, not a mathematical collision-free guarantee — and fill every mandatory field with correctly-sized data. Keep values that define the scenario's expected outcome explicit and fixed. Reserve hardcoded values for tests that validate an external contract itself — a fixed JSON schema, an EDIFACT message, a counterparty code — where the hardcoded value documents the specification rather than arbitrary test logic.
|
||||
|
||||
See sample: [`test-data-must-be-random-and-complete.good.al`](test-data-must-be-random-and-complete.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Looking up a record assumed to already exist (a hardcoded payment method or customer number) instead of creating it, or leaving a mandatory field empty because setup-time validation happens to allow it. Also an anti-pattern, narrower: using a value that doesn't satisfy a scenario's explicit length or format requirement — for example a truncation test that never actually exceeds the field it's meant to overflow.
|
||||
|
||||
See sample: [`test-data-must-be-random-and-complete.bad.al`](test-data-must-be-random-and-complete.bad.al).
|
||||
|
|
@ -0,0 +1,27 @@
|
|||
page 50101 "Customer Info API"
|
||||
{
|
||||
PageType = API;
|
||||
APIPublisher = 'contoso';
|
||||
APIGroup = 'sales';
|
||||
APIVersion = 'v1.0';
|
||||
EntityName = 'customerInfo';
|
||||
EntitySetName = 'customerInfos';
|
||||
SourceTable = Customer;
|
||||
ODataKeyFields = "No.";
|
||||
InsertAllowed = true;
|
||||
|
||||
layout
|
||||
{
|
||||
area(content)
|
||||
{
|
||||
repeater(General)
|
||||
{
|
||||
field(customerNo; Rec."No.")
|
||||
{
|
||||
Editable = false; // consumer must supply "No." on POST — this rejects it
|
||||
}
|
||||
field(name; Rec.Name) { }
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,25 @@
|
|||
page 50101 "Customer Info API"
|
||||
{
|
||||
PageType = API;
|
||||
APIPublisher = 'contoso';
|
||||
APIGroup = 'sales';
|
||||
APIVersion = 'v1.0';
|
||||
EntityName = 'customerInfo';
|
||||
EntitySetName = 'customerInfos';
|
||||
SourceTable = Customer;
|
||||
ODataKeyFields = "No.";
|
||||
InsertAllowed = true;
|
||||
DelayedInsert = true;
|
||||
|
||||
layout
|
||||
{
|
||||
area(content)
|
||||
{
|
||||
repeater(General)
|
||||
{
|
||||
field(customerNo; Rec."No.") { }
|
||||
field(name; Rec.Name) { }
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: web-services
|
||||
keywords: [api-page, key-fields, editable, insert, odata]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Keep Consumer-Provided Key Fields Editable on API Pages
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
A field listed in `ODataKeyFields` cannot have `Editable = false` when the API page allows inserts and the field's value must be supplied by the caller. Marking it read-only removes the field from the OData write schema, so a POST that includes it is rejected as an unknown property. This only applies to keys the consumer must supply — a system-generated key such as `SystemId` is a valid exception, since Business Central assigns its value automatically on insert.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Leave every consumer-supplied key field referenced in `ODataKeyFields` without `Editable = false` on pages where `InsertAllowed = true`, so the OData layer accepts it as a writable property on POST.
|
||||
|
||||
See sample: [`api-page-key-fields-must-be-editable-on-insert.good.al`](api-page-key-fields-must-be-editable-on-insert.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Marking a consumer-provided key field `Editable = false`, out of habit or for perceived safety. This silently breaks create operations with a generic `BadRequest` instead of a clear validation error.
|
||||
|
||||
See sample: [`api-page-key-fields-must-be-editable-on-insert.bad.al`](api-page-key-fields-must-be-editable-on-insert.bad.al).
|
||||
|
|
@ -0,0 +1,24 @@
|
|||
page 50102 "Project Task API"
|
||||
{
|
||||
PageType = API;
|
||||
APIPublisher = 'contoso';
|
||||
APIGroup = 'jobs';
|
||||
APIVersion = 'v1.0';
|
||||
EntityName = 'projectTask';
|
||||
EntitySetName = 'projectTasks';
|
||||
SourceTable = "Project Task";
|
||||
|
||||
layout
|
||||
{
|
||||
area(content)
|
||||
{
|
||||
repeater(General)
|
||||
{
|
||||
// "Remaining Hours" is a stored field, set inside the
|
||||
// OnValidate of "Budgeted Hours" — it goes stale whenever
|
||||
// "Hours Used" changes through any other path.
|
||||
field(remainingHours; Rec."Remaining Hours") { }
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,33 @@
|
|||
page 50102 "Project Task API"
|
||||
{
|
||||
PageType = API;
|
||||
APIPublisher = 'contoso';
|
||||
APIGroup = 'jobs';
|
||||
APIVersion = 'v1.0';
|
||||
EntityName = 'projectTask';
|
||||
EntitySetName = 'projectTasks';
|
||||
SourceTable = "Project Task";
|
||||
DelayedInsert = true;
|
||||
|
||||
layout
|
||||
{
|
||||
area(content)
|
||||
{
|
||||
repeater(General)
|
||||
{
|
||||
field(remainingHours; RemainingHoursCalc) { }
|
||||
field(budgetedHours; Rec."Budgeted Hours") { }
|
||||
field(hoursUsed; Rec."Hours Used") { }
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
trigger OnAfterGetRecord()
|
||||
begin
|
||||
Rec.CalcFields("Hours Used");
|
||||
RemainingHoursCalc := Rec."Budgeted Hours" - Rec."Hours Used";
|
||||
end;
|
||||
|
||||
var
|
||||
RemainingHoursCalc: Decimal;
|
||||
}
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
---
|
||||
bc-version: [all]
|
||||
domain: web-services
|
||||
keywords: [api-page, derived-fields, exposure, odata]
|
||||
technologies: [al]
|
||||
countries: [w1]
|
||||
application-area: [all]
|
||||
---
|
||||
|
||||
# Recalculate Stored Derived Fields Before Exposing Them on API Pages
|
||||
|
||||
> Contributions welcome — open a PR to refine or extend this article.
|
||||
|
||||
## Description
|
||||
|
||||
A stored field whose value is derived from other fields inside an `OnValidate` trigger only updates when that specific trigger fires. If the underlying source data changes through some other path, the stored value goes stale without raising any error. Exposing such a field directly on an API page hands external consumers a snapshot that may be significantly out of date.
|
||||
|
||||
## Best Practice
|
||||
|
||||
Recalculate the derived value in `OnAfterGetRecord` from its authoritative source — typically a FlowField — using a page-level variable, and expose that recalculated value instead of the stale stored field. Whether to also expose the source fields is a separate design decision, not a requirement of this pattern; keep the API contract scoped to what consumers actually need. If letting the consumer verify the recalculation is itself a requirement, expose every field the calculation reads, not just one of them — a derived value with two inputs needs both exposed, or the "verification" is incomplete.
|
||||
|
||||
See sample: [`stored-derived-fields-must-not-be-exposed-directly.good.al`](stored-derived-fields-must-not-be-exposed-directly.good.al).
|
||||
|
||||
## Anti Pattern
|
||||
|
||||
Exposing the stored field directly via `Rec`, trusting that it was kept in sync by whichever trigger last touched it.
|
||||
|
||||
See sample: [`stored-derived-fields-must-not-be-exposed-directly.bad.al`](stored-derived-fields-must-not-be-exposed-directly.bad.al).
|
||||
Loading…
Add table
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Reference in a new issue