Hi all,
i am new to SQLAlchemy (simply wonderful!), and i'm writing some
python scripts to do some experiment.
I've written a SINGLE python module with two classes which define two
different tables (declarative_base) with a simple relationship and a
single Foreign Key and everything WORKS fine as expected. Cool! :P
Then, i've moved that two classes in two different python modules to
better organize my code but now i got the following error:
sqlalchemy.exc.NoReferencedTableError: Could not find table 'metadata'
with which to generate a foreign key
I understood the error message but i can't found a way to resolve this
issue, can you help me?
This is my "directory layout":
test.py - the main python module
SQLTableBuilder_Definition.py - class that define a table called
"Definition"
SQLTableBuilder_Metadata.py - class that define a table called
"Metadata"
test.py:
...
engine = create_engine('sqlite:///test.db3', echo=True,
encoding='utf-8' )
import SQLTableBuilder_Metadata
metadata_table = SQLTableBuilder_Metadata.MetadataClass.__table__
metadata = SQLTableBuilder_Metadata.Base.metadata
metadata.create_all(engine)
import SQLTableBuilder_Definition
definitions_table =
SQLTableBuilder_Definition.DefinitionClass.__table__
metadata = SQLTableBuilder_Definition.Base.metadata
metadata.create_all(engine) <== My script explode here with the
following:
Traceback (most recent call last):
File "test.py", line 82, in <module>
metadata.create_all(engine)
...
sqlalchemy.exc.NoReferencedTableError: Could not find table
'metadata' with which to generate a foreign key
Session = sessionmaker(bind=engine)
Session.configure(bind=engine)
session = Session()
...
session.add(myObj)
...
SQLTableBuilder_Definition.py:
Base = declarative_base()
class DefinitionClass(Base):
__tablename__ = 'definitions'
defId = Column(Integer, primary_key=True)
Id = Column(String)
classType = Column(String)
version = Column(String)
metadataId = Column('metadataId', Integer,
ForeignKey('metadata.metadataId'))
def __init__(self, node):
self.Id = node.get("id")[len(IdName):]
self.version = node.get("version")
self.classType = node.get("class")
SQLTableBuilder_Metadata.py:
import SQLTableBuilder_Definition
Base = declarative_base()
class MetadataClass(Base):
__tablename__ = 'metadata'
metadataId = Column(Integer, primary_key=True)
title = Column(String)
defRef = relation(SQLTableBuilder_Definition.DefinitionClass,
backref="metadata")
def __init__(self, node):
self.title = node
If i remove relation and foreign key from the two classes, everything
works fine again.
I suppose that python can't find the metadata table (previously
created without error) from SQLTableBuilder_Definition.py, but how i
can "point him" in the right direction?
Thanks for your attention.
ps.
>>> print sqlalchemy.__version__
0.6beta1
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