SQLAlchemy-标签字典

简单的答案是 肯定的 。

只需使用关联代理：

from sqlalchemy import Column, Integer, String, Table, create_enginefrom sqlalchemy import orm, metaData, Column, ForeignKeyfrom sqlalchemy.orm import relation, mapper, sessionmakerfrom sqlalchemy.orm.collections import column_mapped_collectionfrom sqlalchemy.ext.associationproxy import association_proxy

创建一个测试环境：

engine = create_engine('sqlite:///:memory:', echo=True)meta = metaData(bind=engine)

定义表：

tb_items = Table('items', meta,         Column('id', Integer, primary_key=True),         Column('name', String(20)),        Column('description', String(100)),    )tb_notes = Table('notes', meta,         Column('id_item', Integer, ForeignKey('items.id'), primary_key=True),        Column('name', String(20), primary_key=True),        Column('value', String(100)),    )meta.create_all()

类（注意

association_proxy

class Note(object):    def __init__(self, name, value):        self.name = name        self.value = valueclass Item(object):    def __init__(self, name, description=''):        self.name = name        self.description = description    notes = association_proxy('_notesdict', 'value', creator=Note)

对应：

mapper(Note, tb_notes)mapper(Item, tb_items, properties={        '_notesdict': relation(Note,   collection_class=column_mapped_collection(tb_notes.c.name)),    })

然后测试一下：

Session = sessionmaker(bind=engine)s = Session()i = Item('ball', 'A round full ball')i.notes['color'] = 'orange'i.notes['size'] = 'big'i.notes['data'] = 'none's.add(i)s.commit()print i.notes

打印：

{u'color': u'orange', u'data': u'none', u'size': u'big'}

但是，那些在注释表中吗？

>>> print list(tb_notes.select().execute())[(1, u'color', u'orange'), (1, u'data', u'none'), (1, u'size', u'big')]

有用！！:)