What I think I'm seeing is that an object can be created even without it's ForeignKeyConstraint being filled.
To run the test code below: $ dropdb test18; createdb test18; python testcode.py This builds on http://groups.google.com/group/sqlalchemy/browse_thread/thread/eb240f3f2555a5e7/ . I understand that the foreign table can't create the referent. (and finding the best idiom for "use one if it exists or create one") is yet be determined. What I truly don't understand is how any instances of "Product" can be created, since there is a FK constraint that is not fulfulled. 1. Is the foreign key constraint fulfilled? 2. Is there a good "create the referent if it doesn't exist, else use it" idiom? 3. Is the polymorphic table business complicating it? It seems liek the compound primary key for A1String is. ---------------- from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import CheckConstraint, ForeignKey, MetaData, PrimaryKeyConstraint from sqlalchemy import ForeignKeyConstraint from sqlalchemy import Table, Column, Integer, Boolean,Unicode,String from sqlalchemy.orm import relation, backref from sqlalchemy import create_engine from sqlalchemy.orm import sessionmaker from sqlalchemy.schema import DDL import sys ECHO = bool((sys.argv + [False])[1]) ## utilties for connecting the db, printing it, etc. def print_schema(T="postgres", Base=None): ''' print print_schema will print the schema in use ''' from StringIO import StringIO buf = StringIO() engine = create_engine('%s://' % T, strategy='mock', executor=lambda s, p='': buf.write(str(s) + p)) Base.metadata.create_all(engine) return buf.getvalue() def db_setup(connstring='sqlite:///:memory:', echo=False, Base=None): engine = create_engine(connstring, echo=echo) Session = sessionmaker(bind=engine, autoflush=False, autocommit=False) session = Session() Base.metadata.bind = engine Base.metadata.create_all() return session, engine def _class_repr(self): ''' print our SA class instances in a nicer way ''' # ugly, use sparingly, may have performance hit d = [(k,v) for k,v in self.__dict__.iteritems() if k[0] != "_"] d = sorted(d, key=lambda x: x[0].lower()) return "<%s, %s>" % (self.__class__, d) Base = declarative_base() class Polystring(Base): __tablename__ = 'strings' id = Column(Integer, nullable=False, primary_key=True) string = Column(String, nullable=False, primary_key=True) origin = Column(String, nullable=False, primary_key=True) __mapper_args__ = {'polymorphic_on': origin} # subtype of string class A1String(Polystring): __mapper_args__ = {'polymorphic_identity': 'a1'} products = relation('Product', order_by="Product.id") class Product(Base): __tablename__ = 'product' __table_args__ = ( ForeignKeyConstraint(['regstring_id', 'regstring', 'regstring_type'], [A1String.id, A1String.string , A1String.origin], on), {} ) id = Column(Integer,primary_key=True) regstring_id = Column(Integer) regstring = Column(String) regstring_type = Column(String,default="asn") ## test code session,eng = db_setup("postgres:///test18", Base=Base, echo=ECHO) add = session.add q = session.query c = session.commit r = _class_repr A = Product(id=192832, regstring="some part id") print r(A) add(A) c() # commit print map(r,q(Product).all()) print "somehow this managed to get in, without making a polystring, which it should be referencing." assert len(q(Polystring).all()) > 0, "So, where is the polystring?" ---------- --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
