SqlSoup相關（）爲多對多拋出異常

我正在使用下面的代碼來使用SqlSoup與現有的數據庫。SqlSoup相關（）爲多對多拋出異常

import sqlalchemy 
from sqlalchemy.ext.sqlsoup import SqlSoup 
from sqlalchemy.orm import backref 

engine = sqlalchemy.create_engine('postgresql:///test') 
db = SqlSoup(engine) 
db.books.relate('author', db.authors) 
db.books.relate('tags', db.tags, secondary=db.tags2books, backref=backref('books', lazy=False))

不過，最後relate()調用拋出一個異常：

Traceback (most recent call last): 
    File "sqlsoup-test.py", line 10, in <module> 
    db.books.relate('tags', db.tags, secondary=db.tags2books, backref=backref('books', lazy=False)) 
    File "/usr/lib64/python2.6/site-packages/sqlalchemy/ext/sqlsoup.py", line 384, in relate 
    class_mapper(cls)._configure_property(propname, relationship(*args, **kwargs)) 
    File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/mapper.py", line 758, in _configure_property 
    prop.init() 
    File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/interfaces.py", line 476, in init 
    self.do_init() 
    File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/properties.py", line 895, in do_init 
    self._determine_joins() 
    File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/properties.py", line 1010, in _determine_joins 
    self.secondary) 
    File "/usr/lib64/python2.6/site-packages/sqlalchemy/orm/properties.py", line 1002, in _search_for_join 
    return join_condition(mapper.local_table, table) 
    File "/usr/lib64/python2.6/site-packages/sqlalchemy/sql/util.py", line 219, in join_condition 
    for fk in b.foreign_keys: 
AttributeError: 'MappedTags2books' object has no attribute 'foreign_keys'

該表已使用以下定義創建：

authors_table = Table('authors', metadata, 
    Column('id', Integer, primary_key=True), 
    Column('name', String, nullable=False, index=True) 
) 

books_table = Table('books', metadata, 
    Column('id', Integer, primary_key=True), 
    Column('author_id', Integer, 
     ForeignKey('authors.id', onupdate='CASCADE', ondelete='CASCADE'), 
     nullable=False), 
    Column('title', String, nullable=False, index=True) 
) 

tags_table = Table('tags', metadata, 
    Column('id', Integer, primary_key=True), 
    Column('tag', String, index=True, unique=True, nullable=False) 
) 

tags2books_table = Table('tags2books', metadata, 
    Column('tag_id', Integer, 
     ForeignKey('tags.id', onupdate='CASCADE', ondelete='CASCADE'), 
     primary_key=True), 
    Column('book_id', Integer, 
     ForeignKey('books.id', onupdate='CASCADE', ondelete='CASCADE'), 
     primary_key=True) 
)

如果你要問「爲什麼他使用SqlSoup時，他可以使用真正的SQLAlchemy？「：我正在寫一篇關於SQLAlchemy的術語表，我在一章中提到了SqlSoup，我想添加一個示例。還有什麼比使用我用於SA示例的數據庫更容易...

來源

2010-11-30 ThiefMaster

看起來像secondary不能是映射類。通過表格修復錯誤：

db.books.relate('tags', db.tags, secondary=db.tags2books._table, backref=backref('books', lazy=False))

來源

2010-12-01 11:31:01 nosklo

SqlSoup相關（）爲多對多拋出異常

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