A parseable file can still be incomplete
A CSV with valid rows does not say whether it covers all products, one warehouse, a filtered selection or only changes since an earlier feed. This is an operational inference, not a promise from the W3C tabular standard. Ask the source owner for the feed type, coverage and completion signal before interpreting an omitted SKU.
- Record supplier, warehouse or catalogue boundary and source-issued version.
- Distinguish zero availability from discontinuation; neither is implied by absence alone.
- A successful download or plausible row count cannot prove source completeness.
Define absence at the coverage boundary
In the synthetic delta example, an omitted item is unchanged. In the complete-snapshot example, an omitted item within the explicitly covered set is marked unavailable under an owner-approved rule, not deleted or declared discontinued. If coverage or completion is unknown, the feed is held and the old state remains. These are example policies, not instructions for any named supplier.
- Apply absence rules only inside the declared coverage, never the whole catalogue.
- Keep explicit discontinuation a separate source operation.
- Do not infer a complete snapshot from a filename such as full.csv.
Make preview changes inspectable
An acceptance fixture has two existing invented items and an incoming update containing only one. The preview must show different results for delta, confirmed-complete snapshot and unknown-completeness cases. It must also show that an item outside coverage is untouched. The feed's mode and source evidence should be visible alongside the proposed changes.
- Hold rather than silently apply an unknown mode.
- A confirmation screen does not authorise a live import.
- This batch provides expected dispositions, not a running supplier connector.
Priced enquiry and non-fit
One feed-change preview or exception interaction in an existing internal web app can be discussed under ship-one-feature-with-running-preview, from £750 after agreeing criteria, an existing private isolated preview and two revision rounds. The offered feature must avoid payment or personal-data changes and use synthetic feed inputs without new accounts or paid services. Supplier retrieval, live stock publication, a new inventory system and historical correction need separate scope. Send invented before/after records and the approved coverage policy initially; the price is untested and payment follows passing checks and buyer sign-off.
- If completeness cannot be established, keep the source updates under the existing authorised operator's review rather than making absence destructive.
Sources and limits
- W3C tabular data model: tables, cells and metadata Checked 2026-10-11.
- The tabular model describes rows, cells, keys and metadata; those structural descriptions do not establish a supplier's full-snapshot or delta contract.
- Existing one-feature preview scope Checked 2026-10-11.