Hello Michael,
On Sunday, March 16, 2014 10:19:16 PM UTC+1, Michael Bayer wrote:
>
>
>
> are you sure it’s actually saying “SET NULL” in the SQL? if the value
> isn’t present in the params, that just means it’s leaving it unaffected.
> this is normal behavior when the value hasn’t changed.
>
> I can’t say much else because these are only excerpts of code without
> context.
>
> if you wanted to show, “stores a NULL”, send a full script that does that
> and asserts it’s the case.
>
Yes, I'm positive, SA explicitly SETs editor_id = NULL. Please find
attached a stand-alone script.
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#!/usr/bin/env python
import logging
import sqlalchemy as sa
import sqlalchemy.orm
import transaction
import zope.sqlalchemy
from sqlalchemy.ext.declarative import (
declared_attr,
declarative_base
)
logging.basicConfig(level=logging.INFO)
lgg = logging.getLogger(__name__)
salgg = logging.getLogger('sqlalchemy.engine')
salgg.setLevel(logging.INFO)
DbEngine = sa.create_engine("postgresql+psycopg2://test:test@localhost/test")
DbSession = sa.orm.scoped_session(
sa.orm.sessionmaker(
extension=zope.sqlalchemy.ZopeTransactionExtension()
)
)
DbSession.configure(bind=DbEngine)
DbBase = declarative_base(bind=DbEngine)
def _validate_editor(context):
pass
# if not context.current_parameters['editor_id']:
# raise ValueError('Editor must be set on update.')
class DefaultMixin(object):
"""Mixin to add Parenchym's standard fields to a model class.
These are: id, ctime, owner, mtime, editor.
"""
id = sa.Column(sa.Integer(), primary_key=True, nullable=False)
"""Primary key of table."""
ctime = sa.Column(sa.DateTime(), server_default=sa.func.current_timestamp(),
nullable=False)
"""Timestamp, creation time."""
# noinspection PyMethodParameters
@declared_attr
def owner_id(cls):
"""ID of user who created this record."""
return sa.Column(
sa.Integer(),
sa.ForeignKey(
"pym.user.id",
onupdate="CASCADE",
ondelete="RESTRICT"
),
nullable=False
)
mtime = sa.Column(sa.DateTime(), onupdate=sa.func.current_timestamp(), nullable=True)
"""Timestamp, last edit time."""
# noinspection PyMethodParameters
@declared_attr
def editor_id(cls):
"""ID of user who was last editor."""
return sa.Column(
sa.Integer(),
sa.ForeignKey(
"pym.user.id",
onupdate="CASCADE",
ondelete="RESTRICT"
),
nullable=True,
onupdate=_validate_editor
)
class User(DbBase, DefaultMixin):
__tablename__ = "user"
__table_args__ = (
{'schema': 'pym'}
)
principal = sa.Column(sa.Unicode(255), nullable=False)
class Tenant(DbBase, DefaultMixin):
"""
A tenant.
"""
__tablename__ = "tenant"
__table_args__ = (
sa.UniqueConstraint('name', name='tenant_ux'),
{'schema': 'pym'}
)
name = sa.Column(sa.Unicode(255), nullable=False)
# Load description only if needed
descr = sa.orm.deferred(sa.Column(sa.UnicodeText, nullable=True))
"""Optional description."""
def __repr__(self):
return "<{name}(id={id}, name='{n}'>".format(
id=self.id, n=self.name, name=self.__class__.__name__)
def setup(sess):
with transaction.manager:
sess.execute("create schema pym")
zope.sqlalchemy.mark_changed(sess)
with transaction.manager:
DbBase.metadata.create_all(DbEngine)
u1 = User()
u1.owner_id = 1
u1.principal = 'salomon'
u2 = User()
u2.owner_id = 1
u2.principal = 'sibylle'
sess.add(u1)
sess.add(u2)
def dance(sess):
lgg.info('=' * 78)
with transaction.manager:
try:
tn = sess.query(Tenant).filter(Tenant.name == 'foo').one()
cnt = tn.descr.count('o')
except sa.orm.exc.NoResultFound:
tn = Tenant()
tn.owner_id = 2
tn.name = 'foo'
tn.descr = 'o'
sess.add(tn)
cnt = 0
lgg.info('Loop {} (added): {} {} {}'.format(cnt, tn.editor_id,
tn.descr, tn.descr.count('o')))
else:
lgg.info('Loop {} (stored before change): {} {} {}'.format(cnt, tn.editor_id,
tn.descr, tn.descr.count('o')))
tn.descr += 'o'
tn.editor_id = 2
lgg.info('-' * 78)
def main():
sess = DbSession()
setup(sess)
dance(sess)
dance(sess)
dance(sess)
dance(sess)
dance(sess)
if __name__ == '__main__':
main()
