类似于Entity Framework的ORM NOT for .NET

Question

What I really like about Entity framework is its drag and drop way of making up the whole model layer of your application. You select the tables, it joins them and you're done. If you update the database scheda, right click -> update and you're done again.

This seems to me miles ahead the competiting ORMs, like the mess of XML (n)Hibernate requires or the hard-to-update Django Models.

Without concentrating on the fact that maybe sometimes more control over the mapping process may be good, are there similar one-click (or one-command) solutions for other (mainly open source like python or php) programming languages or frameworks?

Thanks

Answer 1

SQLAlchemy database reflection gets you half way there. You'll still have to declare your classes and relations between them. Actually you could easily autogenerate the classes too, but you'll still need to name the relations somehow so you might as well declare the classes manually.

The code to setup your database would look something like this:

from sqlalchemy import create_engine, MetaData
from sqlalchemy.ext.declarative import declarative_base

metadata = MetaData(create_engine(database_url), reflect=True)
Base = declarative_base(metadata)    

class Order(Base):
    __table__ = metadata.tables['orders']

class OrderLine(Base):
    __table__ = metadata.tables['orderlines']
    order = relation(Order, backref='lines')

In production code, you'd probably want to cache the reflected database metadata somehow. Like for instance pickle it to a file:

from cPickle import dump, load
import os

if os.path.exists('metadata.cache'):
    metadata = load(open('metadata.cache'))
    metadata.bind = create_engine(database_url)
else:
    metadata = MetaData(create_engine(database_url), reflect=True)
    dump(metadata, open('metadata.cache', 'w'))