Re: [Sqlalchemy-tickets] [sqlalchemy] #2808: AssociationProxy should use keywords on create

[sqlalchemy <mi...@zz...>]

#2808: AssociationProxy should use keywords on create
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      Reporter:  schlamar          |      Owner:  zzzeek
          Type:  enhancement       |     Status:  reopened
      Priority:  medium            |  Milestone:  0.8.xx
     Component:  ext               |   Severity:  minor - half an hour
    Resolution:                    |   Keywords:
Progress State:  completed/closed  |
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Comment (by zzzeek):

 Replying to [comment:11 schlamar]:
 > Plus, your example (with creator) doesn't work because !UserKeyword is
 not yet defined for the User class. So you would have to refactor the
 complete example to make it work (which could be really messy if you have
 to use this solution in production code).

 The my_association_proxy() function doesn't need access to the UserKeyword
 class.    Feel free to actually run the recipe in context of your original
 example:

 {{{
 #!python
 from sqlalchemy import Column, Integer, ForeignKey, String
 from sqlalchemy.orm import relationship, backref

 from sqlalchemy.ext.associationproxy import association_proxy
 from sqlalchemy.ext.declarative import declarative_base

 Base = declarative_base()

 def my_association_proxy(src, target):
     def create(value):
         target_cls = prox.target_class
         return target_cls(**{target: value})
     prox = association_proxy(src, target, creator=create)
     return prox

 class User(Base):
     __tablename__ = 'user'
     id = Column(Integer, primary_key=True)
     name = Column(String(64))
     keywords = my_association_proxy('user_keywords', 'keyword')

 class UserKeyword(Base):
     __tablename__ = 'user_keyword'
     user_id = Column(Integer, ForeignKey('user.id'), primary_key=True)
     keyword_id = Column(Integer, ForeignKey('keyword.id'),
 primary_key=True)

     # bidirectional attribute/collection of "user"/"user_keywords"
     user = relationship(User, backref=backref("user_keywords",
                         cascade="all, delete-orphan"))

     # reference to the "Keyword" object
     keyword = relationship("Keyword")


 class Keyword(Base):
     __tablename__ = 'keyword'
     id = Column(Integer, primary_key=True)
     keyword = Column(String(64))


 user = User(name='log')
 for kw in (Keyword(keyword='new_from_blammo'),
 Keyword(keyword='its_big')):
     user.keywords.append(kw)

 print(user.keywords)
 }}}

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2808#comment:13>
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