bcquality/microsoft/knowledge/data-modeling/share-mediaset-items-with-insert-not-field-assignment.md
Jesper Schulz-Wedde 186d8a1314
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Complete AL review knowledge readiness (#108)
* Complete AL review knowledge readiness

Fill telemetry and Query coverage, strengthen thin review domains, correct audited content defects, and add deterministic cheap-model evaluation and reference-integrity safeguards.

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

Copilot-Session: 9825b012-e653-496a-9310-c1f4b6f8ac27

* Generalize review fixture discovery

Derive smoke cases from the leaf, domain, and paired-sample conventions so new leaves require no scoring-contract changes. Keep only exceptional selection/context overrides and fail when retrieval metadata cannot rank the selected article.

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

Copilot-Session: 9825b012-e653-496a-9310-c1f4b6f8ac27

* Preserve published field IDs in sample

Keep the existing Email and Contact Email field IDs unchanged, clarify that the sample represents an independent baseline, and use a local breaking-change rule for the generic smoke evaluation.

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

Copilot-Session: 9825b012-e653-496a-9310-c1f4b6f8ac27

* Clarify published field identity rules

State explicitly that a published field keeps its ID, name, and type while a replacement is added as a separate field under an unused ID.

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

Copilot-Session: 9825b012-e653-496a-9310-c1f4b6f8ac27

* Align field obsoletion sample baselines

Use Email field ID 3 as the shared baseline so the bad example demonstrates a same-ID rename while the good example retains the original field and adds a separate replacement.

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

Copilot-Session: 9825b012-e653-496a-9310-c1f4b6f8ac27

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Co-authored-by: Jesper Schulz-Wedde <jesper.schulzwedde@microsoft.com>
2026-07-15 10:55:25 +02:00

1.5 KiB

bc-version domain keywords technologies countries application-area
all
data-modeling
mediaset
media
insert
field-assignment
tenant-media
delete-integrity
sharing
al
w1
all

Share MediaSet items with Insert instead of field assignment

Description

Media and MediaSet fields store IDs that reference tenant media system tables. When a record is deleted, the runtime looks for other references only in the same table and field index; it does not scan every table. Directly assigning a media-set field between different table types copies the ID without registering a separate media-set reference, so deleting one record can remove media that the other record still appears to reference.

Best Practice

When sharing media between different tables, iterate the source MediaSet and call Target.MediaSetField.Insert(Source.MediaSetField.Item(Index)), then modify the target record. Direct field assignment is safe only when source and target are the same record subtype and use the same field ID. This concern is about reference/delete integrity, not the separate performance cost of ModifyAll on tables with media fields.

See sample: share-mediaset-items-with-insert-not-field-assignment.good.al.

Anti Pattern

Target.Picture := Source.Picture; where the two variables refer to different table types or different media-field IDs. The code copies an opaque ID, but the platform does not know that two independent fields now share the media object.

See sample: share-mediaset-items-with-insert-not-field-assignment.bad.al.