1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465 |
- from django.apps import apps
- from django.core.management.base import BaseCommand, CommandError
- from django.db import DEFAULT_DB_ALIAS, connections
- from django.db.migrations.executor import MigrationExecutor
- from django.db.migrations.loader import AmbiguityError
-
-
- class Command(BaseCommand):
- help = "Prints the SQL statements for the named migration."
-
- output_transaction = True
-
- def add_arguments(self, parser):
- parser.add_argument('app_label', help='App label of the application containing the migration.')
- parser.add_argument('migration_name', help='Migration name to print the SQL for.')
- parser.add_argument(
- '--database', default=DEFAULT_DB_ALIAS,
- help='Nominates a database to create SQL for. Defaults to the "default" database.',
- )
- parser.add_argument(
- '--backwards', action='store_true',
- help='Creates SQL to unapply the migration, rather than to apply it',
- )
-
- def execute(self, *args, **options):
- # sqlmigrate doesn't support coloring its output but we need to force
- # no_color=True so that the BEGIN/COMMIT statements added by
- # output_transaction don't get colored either.
- options['no_color'] = True
- return super().execute(*args, **options)
-
- def handle(self, *args, **options):
- # Get the database we're operating from
- connection = connections[options['database']]
-
- # Load up an executor to get all the migration data
- executor = MigrationExecutor(connection)
-
- # Resolve command-line arguments into a migration
- app_label, migration_name = options['app_label'], options['migration_name']
- # Validate app_label
- try:
- apps.get_app_config(app_label)
- except LookupError as err:
- raise CommandError(str(err))
- if app_label not in executor.loader.migrated_apps:
- raise CommandError("App '%s' does not have migrations" % app_label)
- try:
- migration = executor.loader.get_migration_by_prefix(app_label, migration_name)
- except AmbiguityError:
- raise CommandError("More than one migration matches '%s' in app '%s'. Please be more specific." % (
- migration_name, app_label))
- except KeyError:
- raise CommandError("Cannot find a migration matching '%s' from app '%s'. Is it in INSTALLED_APPS?" % (
- migration_name, app_label))
- targets = [(app_label, migration.name)]
-
- # Show begin/end around output only for atomic migrations
- self.output_transaction = migration.atomic
-
- # Make a plan that represents just the requested migrations and show SQL
- # for it
- plan = [(executor.loader.graph.nodes[targets[0]], options['backwards'])]
- sql_statements = executor.collect_sql(plan)
- return '\n'.join(sql_statements)
|