FactArticle

There is no way to ALTER an existing SQLite table to make it strict; you have to copy the data out of the non-strict table into a new strict one.

Evan Hahn's post, which inspired the sqlite-utils strict-mode features, notes that SQLite offers no direct ALTER-based path to strict tables, requiring a data copy instead. ✦ AI generated

Evan Hahn · Simon Willison's Weblog · 2026-07-11 · original ↗

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Unfortunately, I don't think there's a way to ALTER a table to make it strict. I think you have to copy the data out of the non-strict table into the strict one.

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✳ SQLite ◉ Evan Hahn

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Mechanism · 1

table.transform() implements the SQLite-documentation-recommended pattern for altering tables beyond what ALTER TABLE supports: create a new temp table with the new schema, copy the data across, then drop the old table and rename the new one into place.Simon Willison · Simon Willison's Weblog · conf 85%

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explains mechanism → sqlite-utils 4.2 adds lots of improvements to the table.transform() feature, which supports complex alter table operations by creating a fresh table, copying across the data, and then dropping and replacing the old one.Simon Willison · Simon Willison's Weblog