Morph is a simple tool to migrate databases on PostgreSQL. It supports rollbacking from other versions without requiring the migration files from the previous version. Hence, to migrate to a new version, you only need the migration files from this particular version.
Each migration file should be prefixed with a numerical identifier. These
identifiers determine the order in which the migrations are going to be ran.
Thus, a good way to avoid conflict with other commiters is to prefix it with a
timestamp formatted as YYYYMMDDHHMM.
Each migration has two SQL files: one ending with .up.sql and the other by
.down.sql, respectively the request to migrate and the one to rollback.
Failing to have a .down.sql file will result in an error when attempting to
rollback but will not prevent the initial migration.
For example, you could have the following files:
migrations/201603291434_create_users.up.sql
CREATE TABLE users (
id serial PRIMARY KEY,
username varchar NOT NULL UNIQUE CHECK (username <> ''),
password varchar NOT NULL CHECK (password <> '')
);
migrations/201603291434_create_users.down.sql
DROP TABLE users;
migrations/201604011203_add_email_to_user.up.sql
ALTER TABLE users ADD COLUMN email varchar;
migrations/201604011203_add_email_to_user.down.sql
ALTER TABLE users DROP COLUMN email;
See morph --help for details about command-line options.