Hello there,
my ORM classes use a mixin that defines a field 'editor_id' which
references a user record.
When I load a freshly created record, editor_id is None, which is correct.
Then I change some values, set editor_id, save it and load it again,
editor_id is correctly set.
Now the strangeness happens: again I change some values and set editor_id,
but use the same value for editor_id it already has, SA stores a NULL value.
This leads to funny alternating behaviour:
1st update: editor_id is set
2nd update: NULL
3rd update set
etc.
Am I doing sth wrong?
Thanks for your help.
Code to reproduce the behaviour (executed in a Pyramid web app):
lgg = logging.getLogger('pym.test')
sess = pym.models.DbSession()
T = pym.authmgr.models.Tenant
try:
tn = sess.query(T).filter(T.name == 'foo').one()
except sa.orm.exc.NoResultFound:
tn = T()
tn.owner_id = request.user.uid
tn.name = 'foo'
tn.descr = 'o'
sess.add(tn)
lgg.debug('Added')
request.session['cnt'] = 0
else:
request.session['cnt'] += 1
lgg.debug('{} {} {} {}'.format(request.session['cnt'], tn.editor_id,
tn.descr, tn.descr.count('o')))
tn.descr += 'o'
tn.editor_id = request.user.uid
Its output:
2014-03-16 14:00:32,812 DEBUG [pym.test][Dummy-2] Added
2014-03-16 14:01:10,268 DEBUG [pym.test][Dummy-4] 1 None o 1
2014-03-16 14:09:23,361 DEBUG [pym.test][Dummy-3] 2 2 oo 2
2014-03-16 14:09:24,301 DEBUG [pym.test][Dummy-4] 3 None ooo 3
2014-03-16 14:09:25,419 DEBUG [pym.test][Dummy-3] 4 2 oooo 4
And this is part of my mixin:
@declared_attr
def editor_id(cls):
"""ID of user who was last editor."""
return Column(
Integer(),
ForeignKey(
"pym.user.id",
onupdate="CASCADE",
ondelete="RESTRICT"
),
nullable=True,
onupdate=_validate_editor
)
The validator was intended to remind me to set editor_id on updates, but I
had to deactivate it because of the above phenomenon:
def _validate_editor(context):
pass
# if not context.current_parameters['editor_id']:
# raise ValueError('Editor must be set on update.')
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