Thx for your quick answer.
About second question
I have event, for example
def track_instances_before_flush(session, context, instances):
for obj in chain(session.new, session.dirty):
if session.is_modified(obj):
print "Before Flush"
table_name = obj.__class__.__dict__['__tablename__']
print "Table_name ---", table_name
print "Raw obj - ", obj
state_before = {}
state_after = {}
mapper = inspect(obj)
attrs = class_mapper(obj.__class__).column_attrs
for attr in attrs:
hist = mapper.attrs[attr.key].history
if hist.has_changes():
state_before[attr.key] = get_history(obj, attr.key)[2][0]
state_after[attr.key] = getattr(obj, attr.key)
print "BEFORE -", state_before
print "AFTER -", state_after
and register it by
listen(app.db.session, 'before_flush', track_instances_before_flush)
and in output i see
Before Flush
Table_name --- MODEL_1
Raw obj - <'MODEL_1' id=2050>
BEFORE - {}
AFTER - {}
In view I change only attr_1 for MODEL_1
On Monday, March 18, 2019 at 4:48:00 PM UTC+2, Mike Bayer wrote:
>
> On Mon, Mar 18, 2019 at 10:30 AM Денис Ралко <ral...@gmail.com
> <javascript:>> wrote:
> >
> > Hi, I have some issue
> >
> > I try implement track logic
> > I have 2 Models and connecting Table
> >
> > My first class
> >
> > class MODEL_1(object):
> > # some values
> >
> > # relations:
> > attr_1 = db.relationship('MODEL_2',
> > secondary="test2test",
> > lazy='dynamic',
> > primaryjoin="MODEL_1.id ==
> test2test.c.first_id",
> > secondaryjoin='test2test.c.second_id ==
> Site.entity_id')
> >
> > Second class
> >
> > class MODEL_2(object):
> > # some values
> > attr_2 = db.relationship('MODEL_1', secondary='test2test',
> lazy='dynamic')
> >
> >
> > And relation table
> >
> >
> > t_ = db.Table(
> > 'test2test',
> > db.Model.metadata,
> >
> > db.Column('first_id', db.Integer,
> > db.ForeignKey('MODEL_1.entity_id'),
> > nullable=False),
> > db.Column('second_id', db.Integer,
> > db.ForeignKey('MODEL_2.id'),
> > nullable=False),
> > db.UniqueConstraint('first_id', 'second_id', name='uq_test2test')
> > )
> >
> >
> > I have some questions
> >
> > 1. can i do some table event what will fire, when will change some
> values in t_ table ?
>
> via the relationship, sure, use @validates or AttributeEvents for
> MODEL_1.attr1, MODEL_2.attr2
>
>
> https://docs.sqlalchemy.org/en/latest/orm/events.html?highlight=attributeevents#sqlalchemy.orm.events.AttributeEvents
>
>
>
> >
> > 2. if i set before_flush event and change some in MODEL_1, event fire,
> but session have no modified objects
>
> you would need to send along a complete example illustrating what you're
> doing.
>
>
>
> >
> > --
> > SQLAlchemy -
> > The Python SQL Toolkit and Object Relational Mapper
> >
> > http://www.sqlalchemy.org/
> >
> > To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
> > ---
> > You received this message because you are subscribed to the Google
> Groups "sqlalchemy" group.
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> an email to sqlalchemy+...@googlegroups.com <javascript:>.
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> <javascript:>.
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> > For more options, visit https://groups.google.com/d/optout.
>
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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