Data model
The map of what your system records, which things exist, what each holds and how they connect, worked out before any screen is designed.
Updated October 2026 · with examples from our own builds
What does data model mean in practice?
The data model decides what the product can know. A quotation, a delivery, a project line or a rescue case: each is a record with fields and links to others. Get it right and features fall out of it; get it wrong and every new feature fights it.
Business rules become concrete here. Whether a product is a priced item or a recipe of parts, whether a quantity is typed or derived from events, whether every record carries a branch: these choices decide what reports, audits and later changes will cost.
A practical test is to take a few real documents, such as invoices or quotations, and check that the model can hold every line without workarounds.
Data model at a glance
- Decides
- What the product can record, report and audit
- Test with
- Real documents from the business
- Expensive to change
- Once live data depends on it
Where has data model come up in our builds?
A product is never a priced SKU: it is a spec sheet composed from reusable spec groups and parts, and its material cost falls out of what it consumes. The model was worked out against 243 spec lines on one real quotation and held when tested against a second of 77 lines.
The core record is a project line, and its sold, ordered, dispatched, received, consumed, invoiced and measured quantities are derived by one function from recorded events, never typed. No application code has been written yet.
Customs import and export, air and sea freight and general jobs become one Job with a type, with mode-specific fields shown only where they apply, in a proposed 22-entity phase-1 model.
Common questions about data model
Should quantities and balances be stored or calculated?
Where they come from events, calculate them. The Firetrix design derives every balance on a project line from purchase orders, receipts and reports, so a balance can't be typed wrong or drift from its history.
How do I check a data model before the build starts?
Feed it real paperwork. If every line of a real quotation or invoice fits without special cases, the model is close; QKE's model was tested this way against two of its real quotations.
Related terms
Planning a product and not sure where data model fits? Ask us, or browse all 116 terms in the glossary.