bcquality/microsoft/knowledge/data-modeling/check-blocked-in-referencing-code-not-in-master.md
Jesper Schulz-Wedde 18cb503540 Add data-modeling and appsource knowledge articles (MICROSOFT layer)
Author 7 remedial BCQuality knowledge articles plus good/bad AL samples
(21 files) covering AL master-table and data-model design:

- data-modeling: master No. from number series in OnInsert; use codeunit
  "No. Series" not obsolete NoSeriesManagement; setup table is a singleton;
  set Last Date Modified in OnModify and OnRename; enforce Blocked in
  referencing code not in the master.
- style: ApplicationArea required on page controls (AS0062).
- appsource: object affixes prevent collisions (AS0011).

Clean-room authored from own BC knowledge; specifics verified against public
sources only (learn.microsoft.com, microsoft/BCApps). Introduces two new
domains (data-modeling, appsource).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-07-01 11:00:05 +02:00

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1.8 KiB
Markdown

---
bc-version: [all]
domain: data-modeling
keywords: [blocked-field, testfield, referencing-code, point-of-use, enforcement, journal-line]
technologies: [al]
countries: [w1]
application-area: [all]
---
# Enforce `Blocked` where the master is used, not in the master itself
## Description
The `Blocked` field on a master record (`Item`, `Customer`, `Resource`, or a custom master) is inert data. The master table holds **no** logic that acts on it. Enforcement belongs in the **consuming** code: when a journal line, document line, or posting routine references the master by its `No.`, that referencing object tests the flag at the point of use, e.g. `LoyaltyMember.Get("Member No."); LoyaltyMember.TestField(Blocked, false);` in the line's `OnValidate` and again before posting.
Putting the block check inside the master's own `OnInsert`/`OnModify` does nothing to stop transactional use: a blocked master is edited rarely, but it is *referenced* constantly, and those references never touch the master's own triggers. Base BC follows this split — `Item.Blocked` is checked by sales/purchase/journal code, not by the `Item` table. A boolean `Blocked` uses `TestField(Blocked, false)`; an option-style block (e.g. `Sales`/`All`) needs the specific option compared at each relevant path.
## Best Practice
The referencing line validates `Master.TestField(Blocked, false)` in `OnValidate` of the reference field and re-checks before posting. The master table stays logic-free on `Blocked`.
See sample: `check-blocked-in-referencing-code-not-in-master.good.al`.
## Anti Pattern
The block check sits in the master's own `OnModify`/`OnInsert` (so referencing and posting proceed unchecked), or there is no check at all on the referencing side.
See sample: `check-blocked-in-referencing-code-not-in-master.bad.al`.