Kent wrote:
> Thanks for your prompt response.
>
> Assuming I fully compose the primary keys, I am still struggling with
> merge():
>
> The model is exactly as I've pasted in my original post, except that
> I've changed the mapper to cascade delete and delete-orphan, since I
> read it would solve my issue...
>
> So the new mapper is:
>
> =======
> orderdetail_mapper = mapper(OrderDetail, order_detail_table,
> properties=dict(parentorder=relation(Order,
> cascade='all,delete-orphan',single_parent=True,
> backref='orderdetails')))
> =======
>
> Start over with a fresh database. Now, I add two "line details" like
> my original post.
>
>
> ================
> ord = Order()
> ord.id = '55'
> ord.customer = 'Kent'
>
> ln1 = OrderDetail()
> ln1.line = 1
> ln1.orderid = '55'
> ln1.product = 'DESK'
>
> ln2 = OrderDetail()
> ln2.line = 2
> ln2.orderid = '55'
> ln2.product = 'WHITESECTIONAL'
>
> ord.orderdetails = [ln1,ln2]
>
> session.add(ord)
> session.flush()
> session.commit()
> ==================
>
>
> This behaves as I expected.
>
> Now, onto merge. Say that ln1 has been deleted and ln3 added:
>
>
> ====
> ord = Order()
> ord.id = '55'
> ord.customer = 'Kent'
>
> ln2 = OrderDetail()
> ln2.line = 2
> ln2.orderid = '55'
> ln2.product = 'WHITESECTIONAL'
>
> ln3 = OrderDetail() # new line
> ln3.line = 3
> ln3.orderid = '55'
> ln3.product = 'CHAIR'
>
> ord.orderdetails = [ln2,ln3]
>
> dbord = session.merge(ord)
> session.commit()
looking through CHANGES I can see mentions of several issues regarding
flushing, merging, and composite primary keys, though none seem quite to
match this particular symptom. in any case 0.5.2 is an old release so I
would ask that you confirm this behavior on 0.5.7.
> ======
>
>
> I expected merge to INSERT ln3 (which it attempts to do) and DELETE
> ln1, which it doesn't do, but fails with this exception:
>
> AssertionError: Dependency rule tried to blank-out primary key column
> 'orderdetails.orderid' on instance '<OrderDetail at 0x2cc5850>'
>
>
> Is my use-case for merge() still not really what it was designed for?
> Can you explain what is going on or what I am doing wrong?
>
>
> Third question: I extrapolate that merge() expects *all* fields are
> populated? In other words, if merge() encounters a field whose value
> is None, will it update that field to null in the database (as opposed
> to leaving the value untouched in the database)? Does None mean
> "leave it alone" or "update to null"?
>
>
>
>
> full output pasted here:
> ===========
> 2010-01-14 02:45:16,296 INFO sqlalchemy.engine.base.Engine.0x...4e50
> BEGIN
> 2010-01-14 02:45:16,296 INFO sqlalchemy.engine.base.Engine.0x...4e50
> SELECT orders.id AS orders_id, orders.customer AS orders_customer
> FROM orders
> WHERE orders.id = :param_1
> 2010-01-14 02:45:16,296 INFO sqlalchemy.engine.base.Engine.0x...4e50
> {'param_1': '55'}
> 2010-01-14 02:45:16,298 INFO sqlalchemy.engine.base.Engine.0x...4e50
> SELECT orderdetails.orderid AS orderdetails_orderid, orderdetails.line
> AS orderdetails_line, orderdetails.product AS orderdetails_product,
> orderdetails.qtyordered AS orderdetails_qtyordered
> FROM orderdetails
> WHERE orderdetails.orderid = :param_1 AND orderdetails.line = :param_2
> 2010-01-14 02:45:16,298 INFO sqlalchemy.engine.base.Engine.0x...4e50
> {'param_1': '55', 'param_2': 2}
> 2010-01-14 02:45:16,302 INFO sqlalchemy.engine.base.Engine.0x...4e50
> SELECT orderdetails.orderid AS orderdetails_orderid, orderdetails.line
> AS orderdetails_line, orderdetails.product AS orderdetails_product,
> orderdetails.qtyordered AS orderdetails_qtyordered
> FROM orderdetails
> WHERE orderdetails.orderid = :param_1 AND orderdetails.line = :param_2
> 2010-01-14 02:45:16,302 INFO sqlalchemy.engine.base.Engine.0x...4e50
> {'param_1': '55', 'param_2': 3}
> 2010-01-14 02:45:16,305 INFO sqlalchemy.engine.base.Engine.0x...4e50
> SELECT orderdetails.qtyordered AS orderdetails_qtyordered
> FROM orderdetails
> WHERE orderdetails.orderid = :param_1 AND orderdetails.line = :param_2
> 2010-01-14 02:45:16,305 INFO sqlalchemy.engine.base.Engine.0x...4e50
> {'param_1': '55', 'param_2': 3}
> /home/rarch/tg2env/lib/python2.6/site-packages/SQLAlchemy-0.5.2-
> py2.6.egg/sqlalchemy/engine/default.py:241: SAWarning: Unicode type
> received non-unicode bind param value 'CHAIR'
> param[key.encode(encoding)] = processors[key](compiled_params[key])
> 2010-01-14 02:45:16,306 INFO sqlalchemy.engine.base.Engine.0x...4e50
> INSERT INTO orderdetails (orderid, line, product, qtyordered) VALUES
> (:orderid, :line, :product, :qtyordered)
> 2010-01-14 02:45:16,307 INFO sqlalchemy.engine.base.Engine.0x...4e50
> {'orderid': '55', 'line': 3, 'product': 'CHAIR', 'qtyordered': None}
> 2010-01-14 02:45:16,308 INFO sqlalchemy.engine.base.Engine.0x...4e50
> SELECT orderdetails.orderid AS orderdetails_orderid, orderdetails.line
> AS orderdetails_line, orderdetails.product AS orderdetails_product,
> orderdetails.qtyordered AS orderdetails_qtyordered
> FROM orderdetails
> WHERE :param_1 = orderdetails.orderid
> 2010-01-14 02:45:16,308 INFO sqlalchemy.engine.base.Engine.0x...4e50
> {'param_1': '55'}
>>>>
>>>>
>>>>
>>>> session.commit()
> 2010-01-14 02:45:30,143 INFO sqlalchemy.engine.base.Engine.0x...4e50
> ROLLBACK
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/session.py", line 673, in
> commit
> self.transaction.commit()
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/session.py", line 378, in
> commit
> self._prepare_impl()
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/session.py", line 362, in
> _prepare_impl
> self.session.flush()
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/session.py", line 1347, in
> flush
> self._flush(objects)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/session.py", line 1417, in
> _flush
> flush_context.execute()
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/unitofwork.py", line 244, in
> execute
> UOWExecutor().execute(self, tasks)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/unitofwork.py", line 707, in
> execute
> self.execute_save_steps(trans, task)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/unitofwork.py", line 724, in
> execute_save_steps
> self.execute_dependencies(trans, task)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/unitofwork.py", line 733, in
> execute_dependencies
> self.execute_dependency(trans, dep, False)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/unitofwork.py", line 719, in
> execute_dependency
> dep.execute(trans, isdelete)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/unitofwork.py", line 686, in
> execute
> delete=delete)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/dependency.py", line 353, in
> process_dependencies
> self._synchronize(state, child, None, False, uowcommit)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/dependency.py", line 395, in
> _synchronize
> sync.clear(state, self.parent, self.prop.synchronize_pairs)
> File "/home/rarch/tg2env/lib/python2.6/site-packages/
> SQLAlchemy-0.5.2-py2.6.egg/sqlalchemy/orm/sync.py", line 28, in clear
> raise AssertionError("Dependency rule tried to blank-out primary
> key column '%s' on instance '%s'" % (r, mapperutil.state_str(dest)))
> AssertionError: Dependency rule tried to blank-out primary key column
> 'orderdetails.orderid' on instance '<OrderDetail at 0x2cc5850>'
>
>
>
>
>
>
>
>
>
>
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