Upper lewel SQLAlchemy migration funcitons.
aiida.backends.sqlalchemy.migrations.env.
run_migrations_offline
Run migrations in ‘offline’ mode.
This configures the context with just a URL and not an Engine, though an Engine is acceptable here as well. By skipping the Engine creation we don’t even need a DBAPI to be available.
Calls to context.execute() here emit the given string to the script output.
run_migrations_online
Run migrations in ‘online’ mode.
In this scenario we need to create an Engine and associate a connection with the context.