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title: "Business Central 29.0: Major Change to Table Extensions and SQL Storage."
summary: Business Central 29.0 changes how table extension fields are stored in the database, moving from a companion-table model to storing extension fields directly in the same SQL table as the base table. This enables cross-table indexes, can improve query performance, and requires developers to avoid direct SQL dependencies.
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# Business Central 29.0: Major Change to Table Extensions and SQL Storage.

[Read the post](https://www.sauravdhyani.com/2026/09/business-central-290-major-change-to.html) · Saurav Dhyani (Saurav Dhyani, MVP) · 2026-09-14 · 2322 words · tier community · reviewed (checked by Opus)

> Business Central 29.0 changes how table extension fields are stored in the database, moving from a companion-table model to storing extension fields directly in the same SQL table as the base table. This enables cross-table indexes, can improve query performance, and requires developers to avoid direct SQL dependencies.

## Key points

- Extension fields now physically reside in the same SQL table as base table fields instead of separate companion tables
- Developers can create indexes spanning both base table and extension fields for more flexible data access patterns
- Database operations involving extensions may perform faster due to co-located storage of all fields
- Partial record loading remains important despite the new storage model; developers should continue using SetLoadFields appropriately
- Solutions should depend on AL and Business Central APIs rather than direct SQL, as physical schema is an implementation detail that can change

## Quotes

- "Developers can define indexes that span fields from a base table and its table extensions." (This new capability enables more flexible data access optimization that was impossible with the previous companion-table approach)

## Context

- Features: Table extension data storage, Cross-table-extension indexing, Partial record loading, SQL column-limit compiler warnings, Data model evolution, Performance optimization for extensions
- Versions: 29.0

Source: Saurav Dhyani, community blog. Summary, key points and quotes are derived (CONTENT-NOTICE.md); read the original for the full text.