superset/migrations/versions/f231d82b9b26_.py

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"""empty message

Revision ID: f231d82b9b26
Revises: e68c4473c581
Create Date: 2018-03-20 19:47:54.991259

"""
import sqlalchemy as sa
from alembic import op

from superset.utils.core import generic_find_uq_constraint_name

# revision identifiers, used by Alembic.
revision = "f231d82b9b26"
down_revision = "e68c4473c581"

conv = {"uq": "uq_%(table_name)s_%(column_0_name)s"}

names = {"columns": "column_name", "metrics": "metric_name"}


def upgrade():

    # Reduce the size of the metric_name column for constraint viability.
    with op.batch_alter_table("metrics", naming_convention=conv) as batch_op:
        batch_op.alter_column(
            "metric_name",
            existing_type=sa.String(length=512),
            type_=sa.String(length=255),
            existing_nullable=True,
        )

    # Add the missing uniqueness constraints.
    for table, column in names.items():
        with op.batch_alter_table(table, naming_convention=conv) as batch_op:
            batch_op.create_unique_constraint(
                "uq_{}_{}".format(table, column), [column, "datasource_id"]
            )


def downgrade():

    bind = op.get_bind()
    insp = sa.engine.reflection.Inspector.from_engine(bind)

    # Restore the size of the metric_name column.
    with op.batch_alter_table("metrics", naming_convention=conv) as batch_op:
        batch_op.alter_column(
            "metric_name",
            existing_type=sa.String(length=255),
            type_=sa.String(length=512),
            existing_nullable=True,
        )

    # Remove the previous missing uniqueness constraints.
    for table, column in names.items():
        with op.batch_alter_table(table, naming_convention=conv) as batch_op:
            batch_op.drop_constraint(
                generic_find_uq_constraint_name(table, {column, "datasource_id"}, insp)
                or "uq_{}_{}".format(table, column),
                type_="unique",
            )