old_contents: """Add periodicity of script
  
  Revision ID: 147d1de2e5e4
  Revises: 
  Create Date: 2019-04-19 18:48:33.526449
  
  """
  from alembic import op
  import sqlalchemy as sa
  
  
  # revision identifiers, used by Alembic.
  revision = '147d1de2e5e4'
  down_revision = None
  branch_labels = None
  depends_on = None
  
  
  def upgrade():
      op.add_column('script', sa.Column('periodicity', sa.String(),server_default='daily'))
  
  
  def downgrade():
      op.drop_column('script', 'periodicity')
  
new_contents: """Add periodicity of script
  
  Revision ID: 147d1de2e5e4
  Revises: 
  Create Date: 2019-04-19 18:48:33.526449
  
  """
  from alembic import op
  import sqlalchemy as sa
  
  
  # revision identifiers, used by Alembic.
  revision = '147d1de2e5e4'
  down_revision = None
  branch_labels = None
  depends_on = None
  
  
  def upgrade():
      op.add_column('script', sa.Column('periodicity', sa.String(),server_default='daily'))
  
  
  def downgrade():
      # Sqlite does not handle the drop column directive, but alembic can take care of
      # creating a migration script if we use its batch mode
      with op.batch_alter_table("script") as batch_op:
          batch_op.drop_column('periodicity')
  
subject: Handle downgrade on a sqlite db