Alembic和枚举类型

Question

为什么下面的代码不工作呢？

new_type = sa.Enum('nonexistent_executable', 'output_limit_exceeded',
               'signal', 'success', 'timed_out', name='status')
old_type = sa.Enum('nonexistent_executable', 'signal', 'success', 'timed_out',
                   name='status')
op.alter_column('testcaseresult', u'status', type_=new_type,
                existing_type=old_type)

Answer 1

Alembic在处理枚举字段时会遇到一些问题

可以试试这个例子

from sqlalchemy.dialects import postgresql    

def upgrade():
    priority = postgresql.ENUM('H', 'M', 'L', name='priority')
    priority.create(op.get_bind())
    # ### commands auto generated by Alembic - please adjust! ###
    op.add_column('tasks', sa.Column('priority', sa.Enum('H', 'M', 'L', name='priority'), nullable=True))
    # ### end Alembic commands ###


def downgrade():
    # ### commands auto generated by Alembic - please adjust! ###
    op.drop_column('tasks', 'priority')
    priority = postgresql.ENUM('H', 'M', 'L', name='priority')
    priority.drop(op.get_bind())
    # ### end Alembic commands ###