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RS-REVERSE-003 — Narrowing a column type can truncate data irreversibly

Namespace: RS-REVERSE · Code: RS-REVERSE-003

Narrowing a column’s type (a wider integer to a smaller one, an unbounded string to a length-limited one, or a fractional number to an integer) can truncate or round values. Widening back cannot restore the lost precision.

Remediation

Section titled “Remediation”

Keep the wider type, or migrate without loss: add a new column of the target type, backfill it while checking every value fits, swap reads and writes over, then drop the old column in a later migration. Take a backup before any in-place narrowing.

References

Section titled “References”
  • PRD §10
  • PRD §12

This page is generated from the same catalog rowshape explain RS-REVERSE-003 reads, so the remediation here is byte-identical to the one a verdict carries — they cannot drift. An agent can read it with the explain_finding MCP tool.