#NAME
PostgreSQL ORM migration
#SYNOPSIS
201305041232_migration_file.hs COMMAND [--with-db-commit]#DESCRIPTION
A Migrations is an executable Haskell source file (e.g. a Haskell source file
with a "main :: IO ()" function, runnable by runghc). It must respond to the
commands "up" and "down" by running a migration and rollback, respectively.
Unless the "--with-db-commit" flag is set, the result of the migration or
rollback should not be committed to the database.
While you can implement a migration however you like, the module
Database.PostgreSQL.Migrations in the postgresql-orm package defines a
function called defaultMain that implements most of the boiler plate
functionality of a migration. You need only implement the actual migration and
rollback code.
#COMMANDS
##up
Upgrade the database by running the migration
##down
Downgrade the database by rolling back the migration
#FLAGS
##--with-db-commit
MUST be included in order to actually commit the migration or rollback to the database. If this argument is not included, a test run is implied, and the migration should affect the database, probably by rolling back the transaction before exiting.
#SEE ALSO
pg_migrate(1), runghc(1)