---
id: feature/573315
type: feature
title: Developers can define indexes that span fields from a base table and its table extensions
summary: "Development: Developers can define indexes that span fields from a base table and its table extensions. Generally available, GA 2026-10 (Microsoft 365 roadmap). The new data model for storing fields from table extensions allows developers to define keys across fields from the base table and table extensions."
tier: official
language: en
system: development
tags:
  - development
review:
  state: derived
  by: null
  at: null
  flags: []
generated:
  at: "2026-10-07T23:41:05.192Z"
  pipeline: 0.2.0
  prompts: {}
  input_hash: 7aec3c23ffe9a341344f9df28866006619b23cffe18de42639090f168ec00163
evidence:
  - kind: roadmap
    url: https://www.microsoft.com/microsoft-365/roadmap?id=573315
    title: Microsoft 365 roadmap 573315
    date: "2026-09-30"
    commit: null
    t: null
    quote: null
  - kind: video
    url: https://www.youtube.com/watch?v=D_Lur52IrIg&t=939s
    title: "What's new in AL and Tools (2026 release wave 2): Mixed extension and base field SQL indexes"
    date: null
    commit: null
    t: 939
    quote: null
  - kind: video
    url: https://www.youtube.com/watch?v=PZVTTem-nZw&t=247s
    title: "Creating TableExtensions in BC29 like we're back in NAV (But Business Central): Cross-app keys in table extensions"
    date: null
    commit: null
    t: 247
    quote: null
  - kind: video
    url: https://www.youtube.com/watch?v=qABlX4AL3GM&t=751s
    title: "Business Central 29.0: Major Change to Table Extensions & SQL.: Cross-field indexes spanning base and extension tables"
    date: null
    commit: null
    t: 751
    quote: null
  - kind: video
    url: https://www.youtube.com/watch?v=Sh3ySQSTw-o&t=397s
    title: "What's new: Server and Database (2026 release wave 2): Cross-table indexes"
    date: null
    commit: null
    t: 397
    quote: null
links:
  learn: []
  objects: []
  features: []
  topics: []
  localizations: []
  videos:
    - video/D_Lur52IrIg
    - video/PZVTTem-nZw
    - video/qABlX4AL3GM
    - video/Sh3ySQSTw-o
  posts: []
  guidelines: []
roadmap_id: "573315"
wave: 2026 release wave 2
status: ga
roadmap_status: Launched
release_phase: General Availability
ga_date: 2026-10
preview_date: null
area: Development
whatsnew_url: null
localizations: []
objects_touched: []
---

# Developers can define indexes that span fields from a base table and its table extensions

> Development: Developers can define indexes that span fields from a base table and its table extensions. Generally available, GA 2026-10 (Microsoft 365 roadmap). The new data model for storing fields from table extensions allows developers to define keys across fields from the base table and table extensions.

[Microsoft 365 roadmap 573315](https://www.microsoft.com/microsoft-365/roadmap?id=573315) · Development · generally available · roadmap status "Launched", phase General Availability

## What Microsoft says

The new data model for storing fields from table extensions allows developers to define keys across fields from the base table and table extensions.

## Dates

- General availability: October CY2026 (2026 release wave 2)
- Public preview: not given
- On the roadmap since 2026-09-30, last changed 2026-09-30

## Covered by

Matched by Haiku among videos and Learn pages in the same galaxy system, checked against the roadmap ids and the evidence text. Every link below was reviewed by Opus.

### Videos

- [What's new in AL and Tools (2026 release wave 2)](../videos/D_Lur52IrIg.md): Mixed extension and base field SQL indexes at [15:39](https://www.youtube.com/watch?v=D_Lur52IrIg&t=939s)
- [Creating TableExtensions in BC29 like we're back in NAV (But Business Central)](../videos/PZVTTem-nZw.md): Cross-app keys in table extensions at [4:07](https://www.youtube.com/watch?v=PZVTTem-nZw&t=247s)
- [Business Central 29.0: Major Change to Table Extensions & SQL.](../videos/qABlX4AL3GM.md): Cross-field indexes spanning base and extension tables at [12:31](https://www.youtube.com/watch?v=qABlX4AL3GM&t=751s)
- [What's new: Server and Database (2026 release wave 2)](../videos/Sh3ySQSTw-o.md): Cross-table indexes at [6:37](https://www.youtube.com/watch?v=Sh3ySQSTw-o&t=397s)

Source: Microsoft 365 roadmap. Status words follow the roadmap.