I'm probably overlooking something simple, looking for feedback before
opening an issue.
I have some objects with relationships defined between. When I create a new
related object and pass it in the append() method of the collection
everything works as expected, the foreign key is set. When I assign the new
related object to a variable and pass that to the append() method, the
foreign key isn't set and I get a 'null value in column "directory_name"
violates not-null constraint'. This is with SQLAlchemy 1.2.5 and python 3.6.
import sqlalchemy as sa
import sqlalchemy.orm as orm
from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
class Directory(Base):
name = sa.Column(sa.String, primary_key=True)
__tablename__ = 'directory'
class Category(Base):
name = sa.Column(sa.String, primary_key=True)
__tablename__ = 'category'
class Filter(Base):
directory_name = sa.Column(sa.String, sa.ForeignKey('directory.name'),
primary_key=True)
category_name = sa.Column(sa.String, sa.ForeignKey('category.name'),
primary_key=True)
filter = sa.Column(sa.String, primary_key=True)
directory = orm.relationship('Directory',
backref=orm.backref('filters', lazy='joined'), lazy='joined')
category = orm.relationship('Category', backref=orm.backref('filters',
lazy='joined'), lazy='joined')
__tablename__ = 'filter'
engine =
sa.create_engine('postgresql+psycopg2://postgres@localhost/bug_test')
Base.metadata.create_all(engine)
session = orm.sessionmaker(bind=engine)()
directory = Directory(name='test')
category_a = Category(name='category a')
category_b = Category(name='category b')
session.add(directory)
session.add(category_a)
session.add(category_b)
session.commit()
assert len(session.new) == 0
# Instantiate object in call to append - works
directory.filters.append(Filter(filter='test filter', category=category_a))
session.commit()
assert len(session.new) == 0
# Instantiate object before call to append - fails
new_filter = Filter(filter='new filter', category=category_b)
directory.filters.append(new_filter)
session.commit()
assert len(session.new) == 0
Thanks,
Derek
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