avdd wrote:
> Is this a bug or am I doing something wrong?
>
> $ cat testordlist.py ; python testordlist.py
these are just known limitations of orderinglist, when it is asked to sort
by primary key. I don't care for this extension very much since it makes
promises that the ORM is not able to keep when it is given primary or
unique key to sort on - the ORM can't magically figure out when object A
with PK 1 is being deleted, and object B is taking over PK 1 in the same
flush, that it needs to change the order of updates/deletes in that case.
the ORM isn't able to do deletes before updates at all, currently. you
need to delete the object individually and flush before altering the
collection.
>
> import sqlalchemy as sql
> from sqlalchemy import orm
> from sqlalchemy.ext.orderinglist import ordering_list
> from sqlalchemy.ext.declarative import declarative_base
>
> engine = sql.create_engine("sqlite:///:memory:")
> metadata = sql.MetaData(bind=engine)
> db = orm.create_session(bind=engine)
>
> T = declarative_base(metadata=metadata)
>
> class A(T):
> __tablename__ = 'a'
> id = sql.Column(sql.Integer, primary_key=True)
> uc = orm.relation('UC', order_by=('i',), cascade='all,delete-
> orphan')
> oc = orm.relation('OC', order_by=('i',), cascade='all,delete-
> orphan',
> collection_class=ordering_list('i'))
> class UC(T):
> __tablename__ = 'uc'
> a_id = sql.Column(sql.Integer, sql.ForeignKey('a.id'),
> primary_key=True)
> i = sql.Column(sql.Integer, primary_key=True)
>
> class OC(T):
> __tablename__ = 'oc'
> a_id = sql.Column(sql.Integer, sql.ForeignKey('a.id'),
> primary_key=True)
> i = sql.Column(sql.Integer, primary_key=True)
>
> metadata.create_all()
>
> a = A(id=1)
> a.oc = [OC(), OC()]
> a.uc = [UC(i=1), UC(i=2)]
>
> with db.begin():
> db.add(a)
> with db.begin():
> del db.query(A).first().uc[0]
> with db.begin():
> del db.query(A).first().oc[0]
>
> Traceback (most recent call last):
> File "testordlist.py", line 40, in <module>
> del db.query(A).first().oc[0]
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> session.py", line 449, in __exit__
> self.commit()
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> session.py", line 378, in commit
> self._prepare_impl()
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> session.py", line 362, in _prepare_impl
> self.session.flush()
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> session.py", line 1354, in flush
> self._flush(objects)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> session.py", line 1432, in _flush
> flush_context.execute()
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> unitofwork.py", line 261, in execute
> UOWExecutor().execute(self, tasks)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> unitofwork.py", line 753, in execute
> self.execute_save_steps(trans, task)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> unitofwork.py", line 768, in execute_save_steps
> self.save_objects(trans, task)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/
> unitofwork.py", line 759, in save_objects
> task.mapper._save_obj(task.polymorphic_tosave_objects, trans)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/orm/mapper.py",
> line 1417, in _save_obj
> c = connection.execute(statement.values(value_params), params)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/engine/
> base.py", line 835, in execute
> return Connection.executors[c](self, object, multiparams, params)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/engine/
> base.py", line 885, in _execute_clauseelement
> return self.__execute_context(context)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/engine/
> base.py", line 907, in __execute_context
> self._cursor_execute(context.cursor, context.statement,
> context.parameters[0], context=context)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/engine/
> base.py", line 961, in _cursor_execute
> self._handle_dbapi_exception(e, statement, parameters, cursor,
> context)
> File "/home/avdd/tmp/src/sqlalchemy.5/lib/sqlalchemy/engine/
> base.py", line 942, in _handle_dbapi_exception
> raise exc.DBAPIError.instance(statement, parameters, e,
> connection_invalidated=is_disconnect)
> sqlalchemy.exc.IntegrityError: (IntegrityError) columns a_id, i are
> not unique u'UPDATE oc SET i=? WHERE oc.a_id = ? AND oc.i = ?' [0, 1,
> 1]
>
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