Check an export before opening it in a spreadsheet

Does the spreadsheet read text or transform it?

CSV does not carry types like a native workbook. Import settings can reinterpret identifiers, dates and cells as numbers or formulas. Combine a dictionary, original copy and reading test. CSV quotation alone does not guarantee text interpretation.

1. Identify sensitive columns

   List leading-zero identifiers, long numeric strings, ambiguous dates, decimals and third-party text. Define the expected type before opening.

2. Use explicit import

   Select known encoding and delimiter. Import identifiers as text. Do not trust double-click defaults; record software version and settings.

3. Test transformations

   Compare original and imported values on a copy. Check that 0012 remains 0012 and ambiguous dates retain meaning. Do not enable external content for the test.

4. Verify the export

   Apply a tested policy for untrusted text in target software. Protection may alter values: separate viewing exports from original data. Recheck after saving and reopening.

Situations and decisions

Typical situations for preparing a check. They do not describe completed assignments or actual observations.

Record to retain

• Original and hash
• Expected column types
• Software and import settings
• Compared values and export policy

Official references

• OWASP — CSV Injection
• W3C — Metadata for tabular data

Related source profiles

• data.gouv.fr
• data.europa.eu
• Insee · Séries chronologiques

Related protocols

• Diagnose a CSV file before using it
• Build a usable data dictionary
• Calculate and compare a file’s SHA-256 digest

Checks before reaching a conclusion

• Are identifiers exact?
• Do dates retain meaning?
• Does untrusted text remain text?
• Was reopening checked?

A tested viewing export and preserved original, with documented transformations.