Support altering columns in SQLite migrations by RENAME-ADD-UPDATE-DROP #333
Description
Since 7bcf9b2, dropping columns in SQLite migrations is possible. We may further support altering columns in SQLite by:
ALTER TABLE "foo" RENAME COLUMN "bar" TO "bar_random_string";
ALTER TABLE "foo" ADD "bar" NEW_TYPE NOT NULL DEFAULT "baz" /* comment */;
-- Do not CAST(x as JSON): https://gerrit.sqlalchemy.org/c/sqlalchemy/alembic/+/2011
UPDATE "foo" SET "bar" = CAST("bar_random_string" as NEW_TYPE);
ALTER TABLE "foo" DROP COLUMN "bar_random_string";