pub fn migrate<C: SqlConn>(conn: &C) -> Result<u32, StoreError>Expand description
Bring the database to SCHEMA_VERSION; returns the version reached.
Each missing migration runs in its own transaction, which re-reads the
version first, so concurrent openers apply it once. Idempotent.
§Errors
StoreError::Unsupported if the database records a newer version than
this binary’s (there is no downgrade; nothing is changed); the engine’s
error otherwise.