Checking the schema and upgrade scripts into source control is extremely important, and this is how I have managed it in the past. (names like table.alter.12.sql). I regret not setting this type of versioning table up from the beginning, though - when you have multiple environments (dev, QA, staging, etc) it can get very confusing in a hurry as to which schema changes have been applied to which databases. With a versioning table and maybe even some deployment time scripts to sanity check versions between the release and the DB, mismatches become immediately apparent.