message: [schema] Adding commits and removing unnecessary foreign-key definitions
diff: @@ -30,7 +30,7 @@ revision = '7f2635b51f5d'
  down_revision = '937d04c16b64'
  from alembic import op
  -from sqlalchemy import Column, engine, ForeignKey, Integer, String
  +from sqlalchemy import Column, engine, Integer, String
  from sqlalchemy.ext.declarative import declarative_base
  from superset import db
  @@ -43,20 +43,20 @@ conv = {
  }
  -class BaseColumnMixin(object):
  +class BaseColumnMixin:
  id = Column(Integer, primary_key=True)
  class DruidColumn(BaseColumnMixin, Base):
  __tablename__ = 'columns'
  - datasource_id = Column(Integer, ForeignKey('datasources.id'))
  + datasource_id = Column(Integer)
  class TableColumn(BaseColumnMixin, Base):
  __tablename__ = 'table_columns'
  - table_id = Column(Integer, ForeignKey('tables.id'))
  + table_id = Column(Integer)
  def upgrade():
  @@ -68,7 +68,9 @@ def upgrade():
  if record.datasource_id is None:
  session.delete(record)
  - # Enforce that the columns.column_name be non-nullable.
  + session.commit()
  +
  + # Enforce that the columns.column_name column be non-nullable.
  with op.batch_alter_table('columns') as batch_op:
  batch_op.alter_column(
  'column_name',
  @@ -81,6 +83,8 @@ def upgrade():
  if record.table_id is None:
  session.delete(record)
  + session.commit()
  +
  # Reduce the size of the table_columns.column_name column for constraint
  # viability and enforce that it be non-nullable.
  with op.batch_alter_table('table_columns') as batch_op:
  