ONS marks non-geographic postcodes (no grid reference) with a placeholder
latitude of 99.999999. The "Latest Centroids" export shipped ~12,789 such
rows, which were imported as real postcodes pointing at lat 99.99 and would
poison nearest-station distance maths. Drop them at ingest, with a test.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Audit item #13. The command truncated postcodes + outcodes immediately
and then chunk-inserted from the CSV. A mid-stream failure (network
drive disconnect, malformed row) left the production tables empty
until a successful re-run.
Now streams into a postcodes_staging table created via Schema::create
(works on both MySQL and SQLite) and only swaps into the live tables
once the full CSV has been consumed. A try/finally ensures the file
handle and staging table are cleaned up on any path. Live data is now
preserved on partial failures.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
