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"""fix sqlite foreign key

Revision ID: 856955da8476
Revises: f23433877c24
Create Date: 2018-06-17 15:54:53.844230

"""

from alembic import op
import sqlalchemy as sa

# revision identifiers, used by Alembic.
revision = '856955da8476'
down_revision = 'f23433877c24'
branch_labels = None
depends_on = None


def upgrade():
    conn = op.get_bind()
    if conn.dialect.name == 'sqlite':
        # Fix broken foreign-key constraint for existing SQLite DBs.
        #
        # Re-define tables and use copy_from to avoid reflection
        # which would fail because referenced user table doesn't exist.
        #
        # Use batch_alter_table to support SQLite workaround.
        chart_table = sa.Table('chart',
                               sa.MetaData(),
                               sa.Column('id', sa.Integer(), nullable=False),
                               sa.Column('label', sa.String(length=200), nullable=True),
                               sa.Column('conn_id', sa.String(length=250), nullable=False),
                               sa.Column('user_id', sa.Integer(), nullable=True),
                               sa.Column('chart_type', sa.String(length=100), nullable=True),
                               sa.Column('sql_layout', sa.String(length=50), nullable=True),
                               sa.Column('sql', sa.Text(), nullable=True),
                               sa.Column('y_log_scale', sa.Boolean(), nullable=True),
                               sa.Column('show_datatable', sa.Boolean(), nullable=True),
                               sa.Column('show_sql', sa.Boolean(), nullable=True),
                               sa.Column('height', sa.Integer(), nullable=True),
                               sa.Column('default_params', sa.String(length=5000), nullable=True),
                               sa.Column('x_is_date', sa.Boolean(), nullable=True),
                               sa.Column('iteration_no', sa.Integer(), nullable=True),
                               sa.Column('last_modified', sa.DateTime(), nullable=True),
                               sa.PrimaryKeyConstraint('id'))
        with op.batch_alter_table('chart', copy_from=chart_table) as batch_op:
            batch_op.create_foreign_key('chart_user_id_fkey', 'users',
                                        ['user_id'], ['id'])

        known_event_table = sa.Table('known_event',
                                     sa.MetaData(),
                                     sa.Column('id', sa.Integer(), nullable=False),
                                     sa.Column('label', sa.String(length=200), nullable=True),
                                     sa.Column('start_date', sa.DateTime(), nullable=True),
                                     sa.Column('end_date', sa.DateTime(), nullable=True),
                                     sa.Column('user_id', sa.Integer(), nullable=True),
                                     sa.Column('known_event_type_id', sa.Integer(), nullable=True),
                                     sa.Column('description', sa.Text(), nullable=True),
                                     sa.ForeignKeyConstraint(['known_event_type_id'],
                                                             ['known_event_type.id'], ),
                                     sa.PrimaryKeyConstraint('id'))
        with op.batch_alter_table('chart', copy_from=known_event_table) as batch_op:
            batch_op.create_foreign_key('known_event_user_id_fkey', 'users',
                                        ['user_id'], ['id'])


def downgrade():
    # Downgrade would fail because the broken FK constraint can't be re-created.
    pass
