[sqlalchemy] Re: M2M relationship

[Heston James - Cold Beans]

> if u look up the stacktrace/traceback, u'll see which statement in 
> your own code triggered the error. is it in the mapping-part or is 
> still in table-declaration part?
> do all 3 tables use same metadata?

Thank you for your comments so far, I appreciate you helping me out on this.
The entire stack trace is below:

Traceback (most recent call last):
  File "test.py", line 9, in <module>
    my_device = post.post("3F8ADE52-4F63-11DD-9AF0-90BB55D89593", "Title",
"Content")
  File "/var/lib/python-support/python2.5/sqlalchemy/orm/attributes.py",
line 1211, in init
    extra_init(class_, oldinit, instance, args, kwargs)
  File "/var/lib/python-support/python2.5/sqlalchemy/orm/mapper.py", line
798, in extra_init
    self.compile()
  File "/var/lib/python-support/python2.5/sqlalchemy/orm/mapper.py", line
350, in compile
    mapper.__initialize_properties()
  File "/var/lib/python-support/python2.5/sqlalchemy/orm/mapper.py", line
371, in __initialize_properties
    prop.init(key, self)
  File "/var/lib/python-support/python2.5/sqlalchemy/orm/interfaces.py",
line 374, in init
    self.do_init()
  File "/var/lib/python-support/python2.5/sqlalchemy/orm/properties.py",
line 467, in do_init
    self.__determine_joins()
  File "/var/lib/python-support/python2.5/sqlalchemy/orm/properties.py",
line 521, in __determine_joins
    self.secondaryjoin = _search_for_join(self.mapper,
self.secondary).onclause
  File "/var/lib/python-support/python2.5/sqlalchemy/orm/properties.py",
line 514, in _search_for_join
    return sql.join(mapper.local_table, table)
  File "/var/lib/python-support/python2.5/sqlalchemy/sql/expression.py",
line 116, in join
    return Join(left, right, onclause, isouter)
  File "/var/lib/python-support/python2.5/sqlalchemy/sql/expression.py",
line 2275, in __init__
    self.onclause = self.__match_primaries(self.left, self.right)
  File "/var/lib/python-support/python2.5/sqlalchemy/sql/expression.py",
line 2317, in __match_primaries
    return sql_util.join_condition(primary, secondary)
  File "/var/lib/python-support/python2.5/sqlalchemy/sql/util.py", line 74,
in join_condition
    col = fk.get_referent(a)
  File "/var/lib/python-support/python2.5/sqlalchemy/schema.py", line 755,
in get_referent
    return table.corresponding_column(self.column)
  File "/var/lib/python-support/python2.5/sqlalchemy/schema.py", line 788,
in column
    "foreign key" % tname)
sqlalchemy.exceptions.NoReferencedTableError: Could not find table 'post'
with which to generate a foreign key

I've also attached the two modules and the test script I'm trying to use, if
you wouldn't mind taking a look an letting me know what I'm doing wrong, I
would really appreciate it.

Cheers,

Heston

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# Class Imports
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Table, Column, Integer, String, MetaData, ForeignKey

# Configure the delarative base for SQL Alchemy.
Base = declarative_base()

# Define the Remote Device class.
class keyword(Base):
    
    # Define the table for SQL Aclchemy
    __tablename__ = "keyword"

    # Define the class properties for SQL Alchemy
    keyword_id = Column(Integer, primary_key=True)
    word = Column(String)
    
    # I'm the class constructor method.
    def __init__(self, keyword_id="", word=""):
        self.keyword_id = keyword
        self.word = word
        
# Class Imports
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Table, Column, Integer, String, MetaData, ForeignKey
from sqlalchemy.orm import relation, backref
import keyword

# Configure the delarative base for SQL Alchemy.
Base = declarative_base()

metadata = MetaData()

post_keyword = Table("post_keyword", metadata,
                      Column("post_id", String, ForeignKey('post.post_id')),
                      Column('keyword_id', Integer, 
ForeignKey('keyword.keyword_id'))
)

# Define the Remote Device class.
class post(Base):
    
    # Define the table for SQL Aclchemy
    __tablename__ = "post"

    # Define the class properties for SQL Alchemy
    post_id = Column(String, primary_key=True)
    title = Column(String)
    content = Column(String)
    
    # many to many BlogPost<->Keyword
    keywords = relation(keyword.keyword, secondary=post_keyword, backref="post")
    
    # I'm the class constructor method.
    def __init__(self, post_id="", title="", content=""):
        self.post_id = post_id
        self.title = title
        self.content = content
import post
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

engine = create_engine("connectionstring", echo=False)
Session = sessionmaker(bind=engine)
my_session = Session()

my_device = post.post("3F8ADE52-4F63-11DD-9AF0-90BB55D89593", "Title", 
"Content")

my_session.save_or_update(my_device)
my_session.commit()