- Feature
- Define indexes spanning base-table and extension fields
- Availability
- Generally available (October 2026)
- Industry focus
- Agribusiness (grain merchants, produce packers and farm supply cooperatives)
Agribusinesses rarely fit a standard ERP data model. Grain merchants, produce packers and farm supply cooperatives add fields for crop year, variety, grower, field, quality grade and contract type. Those custom fields drive their most important lookups and reports. Business Central 29.0 lets developers index them properly alongside standard fields.
The industry challenge
In Business Central, custom fields usually come from table extensions. A grain merchant might extend the item ledger, purchase lines and sales lines with fields like:
- Crop year and harvest season
- Grower or member number
- Quality grade (protein, moisture, screenings)
- Contract or pool reference
The most common questions combine standard and custom fields. What did we buy from this vendor (standard) for crop year 2026 (custom), by posting date (standard)? What stock of this item (standard) is at grade A (custom) in each location (standard)?
Until now, developers couldn't define one index (key) that mixed base-table fields with extension fields. Queries on those combinations were slower than they should have been, especially on large ledger tables. Developers worked around it with duplicate fields, extra code or slow reports.
What Microsoft delivered in Business Central 29.0
Business Central 29.0 introduces a new data model for storing table extension fields. All fields on an AL table, both standard and extension, are now stored in the same database table. Microsoft says this delivers faster performance on database operations involving table extensions.
Building on that, developers can now define keys that span fields from the base table and its table extensions. A table extension's key can mix standard and custom fields.
Where the value shows up
| Business area | Impact for an agribusiness |
|---|---|
| Reporting | Faster reports by crop year, grade, grower and date |
| Daily operations | Quicker lookups at intake and dispatch during harvest |
| Data design | No need for duplicate fields just to make indexing work |
| Performance at peak | Better behaviour on large ledgers during the harvest rush |
| Development cost | Simpler extensions that are easier to maintain |
Harvest is when performance matters most. Intake weighbridges, grading and contract allocation all run at once, and slow lookups create queues of trucks. Better indexing on the fields that matter can make a visible difference.
A worked scenario
Consider a grain cooperative with 1,200 grower members (an illustrative example). Its extension adds crop year, grower number and grade to purchase and item ledger entries. During harvest, intake staff need to see each grower's deliveries for the current crop year to check against contracts.
Before 29.0, that lookup mixed a standard field (vendor) with custom fields (crop year and grade), and no index covered all of them. At peak, the page took several seconds to load, and staff at busy sites complained.
With Business Central 29.0, the developer defines a key that combines the vendor number, crop year and posting date. The lookup becomes noticeably quicker, and the end-of-season pool report that groups deliveries by grower and grade benefits too.
Adoption considerations
- Find the slow, mixed queries. Focus on lookups and reports that filter on both standard and custom fields.
- Don't over-index. Every index slows writes and uses storage. Add only what your critical processes need.
- Measure with real data. Test with a full season's volumes in a sandbox.
- Retire workarounds. Duplicate fields created just for performance may no longer be needed.
- Coordinate with app publishers. If custom fields come from a vertical app, ask whether the publisher plans to use mixed keys.
The bottom line
Agribusinesses make their ERP their own with custom fields, and those fields drive their most important decisions. Mixed-table indexes in Business Central 29.0 mean those custom fields can finally perform as well as standard ones. For businesses that live or die by harvest-time speed, that's a meaningful change.
If your Business Central system slows down at peak periods, it's worth reviewing your extension data model and indexes with an experienced adviser.
Sources: Microsoft roadmap 573315 · Microsoft roadmap 573332