"""Add is_fork column to projects

Revision ID: 1d18843a1994

Revises: 32d636cb5e00

Create Date: 2016-07-17 22:02:14.495146

"""

# revision identifiers, used by Alembic.

revision = '1d18843a1994'

down_revision = '32d636cb5e00'

from alembic import op

import sqlalchemy as sa

def upgrade():

    ''' Add is_fork column to project table'''

    op.add_column(

        'projects',

        sa.Column(

            'is_fork', sa.Boolean,

            default=False,

            nullable=True)

    )

    op.execute('''UPDATE "projects" '''

               '''SET is_fork=TRUE WHERE parent_id IS NOT NULL;''')

    op.execute('''UPDATE "projects" '''

               '''SET is_fork=FALSE WHERE parent_id IS NULL;''')

    op.alter_column(

        'projects', 'is_fork',

        nullable=False, existing_nullable=True)

def downgrade():

    ''' Revert the _is_fork column added'''

    op.drop_column('projects', 'is_fork')