python - 使用 alembic 获取表值并更新到另一个表。

Question

我在 client 表中有 oauth secret 和 oauth key。现在我将它们移动到将在迁移期间创建的 oauth credentials 表中。 Alembic 生成了以下升级模式。

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')

一旦脚本进入 clients 或 connection.execute，alembic 脚本就会挂起。启用 sqlalchemy logs 后，Base.Engine 为空。也试过op.execute，没有运气。

日志

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？

Answer 1

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 ###