"""Cascade deleting flags when tokens are deleted

Revision ID: 2b1743f77436

Revises: 5993f9240bcf

Create Date: 2019-01-16 13:38:34.954904

"""

from alembic import op

import sqlalchemy as sa

# revision identifiers, used by Alembic.

revision = '2b1743f77436'

down_revision = '5993f9240bcf'

def upgrade():

    """ Remove the existing foreign key in pull_request_flags.token_id and

    re-create it with CASCADE on delete and update.

    """

    # alter the constraints

    op.drop_constraint(

        'pull_request_flags_token_id_fkey', 'pull_request_flags',

        type_='foreignkey')

    op.create_foreign_key(

        u'pull_request_flags_token_id_fkey',

        'pull_request_flags',

        'tokens',

        ['token_id'],

        ['id'],

        ondelete="CASCADE",

        onupdate="CASCADE",

    )

def downgrade():

    """ Remove the existing foreign key in pull_request_flags.token_id and

    re-create it with without specifying the behavior on delete and update.

    """

    op.drop_constraint(

        'pull_request_flags_token_id_fkey', 'pull_request_flags',

        type_='foreignkey')

    op.create_foreign_key(

        u'pull_request_flags_token_id_fkey',

        'pull_request_flags',

        'tokens',

        ['token_id'],

        ['id'],

    )