使用alembic获取表值并更新到另一个表。

时间：2013-09-10 18:40:48

标签： python sqlalchemy alembic

我在oauth secret表中有oauth key和client。现在我将它们移动到将在迁移期间创建的oauth credentials表。 Alembic生成以下架构进行升级。 

from myapp.models import Client, ClientCredential
from alembic import op
import sqlalchemy as sa


def upgrade():
### commands auto generated by Alembic - please adjust! ###
    op.create_table('client_credential',
    sa.Column('id', sa.Integer(), nullable=False),
    sa.Column('created_at', sa.DateTime(), nullable=False),
    sa.Column('updated_at', sa.DateTime(), nullable=False),
    sa.Column('client_id', sa.Integer(), nullable=False),
    sa.Column('key', sa.String(length=22), nullable=False),
    sa.Column('secret', sa.String(length=44), nullable=False),
    sa.Column('is_active', sa.Boolean(), nullable=False),
    sa.ForeignKeyConstraint(['client_id'], ['client.id'], ),
    sa.PrimaryKeyConstraint('id'),
    sa.UniqueConstraint('key')
   )
   # Here I need to copy data from table A to newly created Table.
   # Now Client table will not have secret and key attributes
   clients = [{'secret': client.secret, 'key': client.key, 'is_active':True, 'client_id': client.id, 'created_at': sa.func.now(), 'updated_at': sa.func.now()} for client in Client.query.all()]
   op.bulk_insert(ClientCredential, clients)
   #Also replaced above two lines with 
   #connection = op.get_bind()
   #print connection.execute(Client, Client.query.all())
   op.drop_column(u'client', u'secret')
   op.drop_column(u'client', u'key')

脚本输入clients或connection.execute后，alembic脚本挂起。启用sqlalchemy logs后，Base.Engine为空。还试过op.execute，没有运气。

Log 

INFO  [alembic.migration] Context impl PostgresqlImpl.
INFO  [alembic.migration] Will assume transactional DDL.
INFO  [alembic.migration] Running upgrade 25e7a9839cd4 -> 176fb70348b9, Added  ClientCredential
2013-09-10 23:59:08,144 INFO sqlalchemy.engine.base.Engine select version()
INFO  [sqlalchemy.engine.base.Engine] select version()
2013-09-10 23:59:08,145 INFO sqlalchemy.engine.base.Engine {}
INFO  [sqlalchemy.engine.base.Engine] {}
2013-09-10 23:59:08,146 INFO sqlalchemy.engine.base.Engine select current_schema()
INFO  [sqlalchemy.engine.base.Engine] select current_schema()
2013-09-10 23:59:08,146 INFO sqlalchemy.engine.base.Engine {}
INFO  [sqlalchemy.engine.base.Engine] {}
2013-09-10 23:59:08,148 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
INFO  [sqlalchemy.engine.base.Engine] BEGIN (implicit)
2013-09-10 23:59:08,150 INFO sqlalchemy.engine.base.Engine SELECT client.id AS client_id,    client.created_at AS client_created_at, client.updated_at AS client_updated_at, client.user_id   AS client_user_id, client.org_id AS client_org_id, client.title AS client_title,   client.description AS client_description, client.website AS client_website, client.redirect_uri AS client_redirect_uri, client.notification_uri AS   client_notification_uri, client.iframe_uri AS client_iframe_uri, client.resource_uri AS client_resource_uri, client.active AS client_active, client.allow_any_login AS client_allow_any_login, client.team_access AS client_team_access, client.trusted AS client_trusted
FROM client
INFO  [sqlalchemy.engine.base.Engine] SELECT client.id AS client_id, client.created_at AS    client_created_at, client.updated_at AS client_updated_at, client.user_id AS client_user_id, client.org_id AS client_org_id, client.title AS client_title, client.description AS client_description, client.website AS client_website, client.redirect_uri AS client_redirect_uri, client.notification_uri AS client_notification_uri, client.iframe_uri AS client_iframe_uri, client.resource_uri AS client_resource_uri, client.active AS client_active, client.allow_any_login AS client_allow_any_login, client.team_access AS client_team_access, client.trusted AS client_trusted
FROM client
2013-09-10 23:59:08,150 INFO sqlalchemy.engine.base.Engine {}
INFO  [sqlalchemy.engine.base.Engine] {}

如何使用alembic迁移将值从client表复制到client_credential表？

3 个答案:

答案 0 :(得分：27)

最后我解决了这个问题。创建原始sql以获取值并使用bulk_insert。

def upgrade():
    ### commands auto generated by Alembic - please adjust! ###
    op.create_table('client_credential',
    sa.Column('id', sa.Integer(), nullable=False),
    sa.Column('created_at', sa.DateTime(), nullable=False),
    sa.Column('updated_at', sa.DateTime(), nullable=False),
    sa.Column('client_id', sa.Integer(), nullable=False),
    sa.Column('key', sa.String(length=22), nullable=False),
    sa.Column('secret', sa.String(length=44), nullable=False),
    sa.Column('is_active', sa.Boolean(), nullable=False),
    sa.ForeignKeyConstraint(['client_id'], ['client.id'], ),
    sa.PrimaryKeyConstraint('id'),
    sa.UniqueConstraint('key')
    )
    #http://stackoverflow.com/questions/15725859/sqlalchemy-alembic-bulk-insert-fails-str-object-has-no-attribute-autoincre
    client_credential = sa.sql.table('client_credential',
        sa.Column('client_id', sa.Integer, nullable=False),
        sa.Column('is_active', sa.Boolean, nullable=False, default=True),
        sa.Column('key', sa.String(22), nullable=False, default=True),
        sa.Column('secret', sa.String(22), nullable=False, default=True),
        sa.Column('created_at', sa.DateTime, nullable=False, default=sa.func.now()),
        sa.Column('updated_at', sa.DateTime, nullable=False, default=sa.func.now()),
    )
    conn = op.get_bind()
    res = conn.execute("select secret, key, id from client")
    results = res.fetchall()
    clients = [{'secret': r[0], 'key': r[1], 'is_active':True, 'client_id': r[2], 'created_at': datetime.datetime.now(), 'updated_at': datetime.datetime.now()} for r in results]
    op.bulk_insert(client_credential, clients)
    op.drop_column(u'client', u'secret')
    op.drop_column(u'client', u'key')
    ### end Alembic commands ###

答案 1 :(得分：2)

您可以使用sqlalchemy引擎绑定创建DBSession，然后就可以避免使用SQL查询。

from myapp.models import Client, ClientCredential
from alembic import op, context
import sqlalchemy as sa


def upgrade():
    ### commands auto generated by Alembic - please adjust! ###
    url = context.config.get_main_option("sqlalchemy.url")
    engine = sa.create_engine(url)
    DBSession.configure(bind=engine)

    op.create_table(
        'client_credential',
        sa.Column('id', sa.Integer(), nullable=False),
        sa.Column('created_at', sa.DateTime(), nullable=False),
        sa.Column('updated_at', sa.DateTime(), nullable=False),
        sa.Column('client_id', sa.Integer(), nullable=False),
        sa.Column('key', sa.String(length=22), nullable=False),
        sa.Column('secret', sa.String(length=44), nullable=False),
        sa.Column('is_active', sa.Boolean(), nullable=False),
        sa.ForeignKeyConstraint(['client_id'], ['client.id'], ),
        sa.PrimaryKeyConstraint('id'),
        sa.UniqueConstraint('key'))
    # Here I need to copy data from table A to newly created Table.
    # Now Client table will not have secret and key attributes
    clients = [
        {'secret': client.secret,
         'key': client.key,
         'is_active': True,
         'client_id': client.id,
         'created_at': sa.func.now(),
         'updated_at': sa.func.now()}
        for client in Client.query.all()]
    op.bulk_insert(ClientCredential, clients)
    #Also replaced above two lines with
    #connection = op.get_bind()
    #print connection.execute(Client, Client.query.all())
    op.drop_column(u'client', u'secret')
    op.drop_column(u'client', u'key')

答案 2 :(得分：0)

也许尝试添加column_reflect侦听器？例如：

def listen_for_reflect(inspector, table, column_info):
    "correct an ENUM type"
    if column_info['name'] == 'my_enum':
        column_info['type'] = Enum('a', 'b', 'c')

with self.op.batch_alter_table(
    "bar",
    reflect_kwargs=dict(
        listeners=[
            ('column_reflect', listen_for_reflect)
        ]
    )
) as batch_op:
    batch_op.alter_column(
        'flag', new_column_name='bflag', existing_type=Boolean)

更多信息：https://alembic.zzzcomputing.com/en/latest/batch.html#controlling-table-reflection

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