old_contents: import os
  # Importing this is what gets our model available for Alembic.
  import model.database # pylint: disable=unused-import
  import sqlalchemy as sa
  
  from sqlalchemy.ext.compiler import compiles
  from sqlalchemy.types import BLOB
  from sqlalchemy.dialects.mysql.types import TINYINT, SMALLINT
  from alembic import context
  from sqlalchemy import create_engine
  from logging.config import fileConfig
  from model.base import Base
  
  
  # this is the Alembic Config object, which provides
  # access to the values within the .ini file in use.
  config = context.config
  
  # Interpret the config file for Python logging.
  # This line sets up loggers basically.
  fileConfig(config.config_file_name)
  
  # add your model's MetaData object here
  # for 'autogenerate' support
  # from myapp import mymodel
  # target_metadata = mymodel.Base.metadata
  target_metadata = Base.metadata
  
  # other values from the config, defined by the needs of env.py,
  # can be acquired:
  # my_important_option = config.get_main_option("my_important_option")
  # ... etc.
  
  # In MySQL, make BLOB fields be LONGBLOB (which supports large blobs)
  @compiles(BLOB, "mysql")
  def compile_blob_in_mysql_to_longblob(type_, compiler, **kw):
    #pylint: disable=unused-argument
    return "LONGBLOB"
  
  def get_url():
    return os.environ['DB_CONNECTION_STRING']
  
  def my_compare_type(ctx, inspected_column, metadata_column, inspected_type, metadata_type):
     #pylint: disable=unused-argument
  
    # return True if the types are different,
    # False if not, or None to allow the default implementation
    # to compare these types
    if isinstance(metadata_type, sa.Boolean) and isinstance(inspected_type, TINYINT):
      return False
    if isinstance(metadata_type, model.utils.Enum) and isinstance(inspected_type, SMALLINT):
      return False
    return None
  
  def 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.
  
    """
    url = get_url()
    context.configure(
        url=url, target_metadata=target_metadata, literal_binds=True, compare_type=my_compare_type)
  
    with context.begin_transaction():
      context.run_migrations()
  
  
  def run_migrations_online():
    """Run migrations in 'online' mode.
  
    In this scenario we need to create an Engine
    and associate a connection with the context.
  
    """
    connectable = create_engine(get_url())
  
    with connectable.connect() as connection:
      context.configure(
            connection=connection,
            target_metadata=target_metadata,
            compare_type=my_compare_type
      )
  
      with context.begin_transaction():
        context.run_migrations()
  
  if context.is_offline_mode():
    run_migrations_offline()
  else:
    run_migrations_online()
  
new_contents: import os
  # Importing this is what gets our model available for Alembic.
  import model.database # pylint: disable=unused-import
  import sqlalchemy as sa
  
  from sqlalchemy.ext.compiler import compiles
  from sqlalchemy.types import BLOB
  from sqlalchemy.dialects.mysql.types import TINYINT, SMALLINT
  from alembic import context
  from sqlalchemy import create_engine
  from logging.config import fileConfig
  from model.base import Base
  
  
  # this is the Alembic Config object, which provides
  # access to the values within the .ini file in use.
  config = context.config
  
  # Interpret the config file for Python logging.
  # This line sets up loggers basically.
  fileConfig(config.config_file_name)
  
  # add your model's MetaData object here
  # for 'autogenerate' support
  # from myapp import mymodel
  # target_metadata = mymodel.Base.metadata
  target_metadata = Base.metadata
  
  # other values from the config, defined by the needs of env.py,
  # can be acquired:
  # my_important_option = config.get_main_option("my_important_option")
  # ... etc.
  
  # In MySQL, make BLOB fields be LONGBLOB (which supports large blobs). This
  # is required for (at least) Questionnaires with, for example, 1000+ questions.
  @compiles(BLOB, "mysql")
  def compile_blob_in_mysql_to_longblob(type_, compiler, **kw):
    #pylint: disable=unused-argument
    return "LONGBLOB"
  
  def get_url():
    return os.environ['DB_CONNECTION_STRING']
  
  def my_compare_type(ctx, inspected_column, metadata_column, inspected_type, metadata_type):
     #pylint: disable=unused-argument
  
    # return True if the types are different,
    # False if not, or None to allow the default implementation
    # to compare these types
    if isinstance(metadata_type, sa.Boolean) and isinstance(inspected_type, TINYINT):
      return False
    if isinstance(metadata_type, model.utils.Enum) and isinstance(inspected_type, SMALLINT):
      return False
    return None
  
  def 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.
  
    """
    url = get_url()
    context.configure(
        url=url, target_metadata=target_metadata, literal_binds=True, compare_type=my_compare_type)
  
    with context.begin_transaction():
      context.run_migrations()
  
  
  def run_migrations_online():
    """Run migrations in 'online' mode.
  
    In this scenario we need to create an Engine
    and associate a connection with the context.
  
    """
    connectable = create_engine(get_url())
  
    with connectable.connect() as connection:
      context.configure(
            connection=connection,
            target_metadata=target_metadata,
            compare_type=my_compare_type
      )
  
      with context.begin_transaction():
        context.run_migrations()
  
  if context.is_offline_mode():
    run_migrations_offline()
  else:
    run_migrations_online()
  
subject: Add comment explaining requirement for LONGBLOB. (#257)