SQLAlchemy - 创建表模板

Question

我刚开始学习SQLAlchemy，最近在想……我会在我的模型中有很多表。我希望每个表都有自己的文件。

我现在使用的代码是：

from sqlalchemy import MetaData
from sqlalchemy.orm import scoped_session, sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.dialects import postgresql
import sqlalchemy as sa

__all__ = ['Session', 'engine', 'metadata']

# SQLAlchemy database engine. Updated by model.init_model()
engine = None

# SQLAlchemy session manager. Updated by model.init_model()
Session = scoped_session(sessionmaker())

# Global metadata. If you have multiple databases with overlapping table
# names, you'll need a metadata for each database
metadata = MetaData()

# declarative table definitions
Base = declarative_base()
Base.metadata = metadata

schema = 'srbam_dev'

在meta.py文件中

在_init_.py文件中写以下内容

"""The application's model objects"""
import sqlalchemy as sa
from sqlalchemy import orm

from models import meta
from models.filers import Filer
from models.vfilers import Vfiler
from models.filer_options import FilerOption

def init_models(engine):
    """Call me before using any of the tables or classes in the model"""
    ## Reflected tables must be defined and mapped here
    #global reflected_table
    #reflected_table = sa.Table("Reflected", meta.metadata, autoload=True,
    #                           autoload_with=engine)
    #orm.mapper(Reflected, reflected_table)
    #
    meta.engine = sa.create_engine(engine)
    meta.Session.configure(bind=meta.engine)

    class Basic_Table(object):
        id = sa.Column(
            postgresql.UUID(),
            nullable=False,
            primary_key=True
            )
        created = sa.Column(
            sa.types.DateTime(True),
            nullable=False
            )
        modified = sa.Column(
            sa.types.DateTime(True),
            nullable=False
            )

然后在我所有的模型中写以下内容

from models.meta import Base
from models.meta import Basic_Table
from models.meta import schema
import sqlalchemy as sa
from sqlalchemy.dialects import postgresql

class Filer(Base,Basic_Table):

这样做没问题，只要我不开始在表中使用外键。一旦我使用了外键，比如说

sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 't_vfilers.filer_id' could not find table 't_filers' with which to generate a foreign key to target column 'id'

我尝试直接在Filer类中定义id键（并从声明中移除Basic_Table），但这并没有解决问题。

我创建数据库的代码看起来是这样的：

#!/usr/bin/python
import ConfigParser
from sqlalchemy.engine.url import URL
from models import *

config = ConfigParser.RawConfigParser()
config.read('conf/core.conf')
db_url = URL(
    'postgresql+psycopg2',
    config.get('database','username'),
    config.get('database','password'),
    config.get('database','host'),
    config.get('database','port'),
    config.get('database','dbname')
    )

init_models(db_url)
meta.Base.metadata.drop_all(bind=meta.engine)
meta.Base.metadata.create_all(bind=meta.engine)

有没有人知道怎么解决这个问题吗？

orm 数据库管理 sqlalchemy 数据库设计外键 python库模块化表模型

SQLAlchemy - 创建表模板

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