ColumnProperty merge from nonexistent prop shouldn't expire loaded prop if load=True

[Mike Bayer]

it should likely reset any history on the attribute, considering that the next load operation in the trans would get that value from an expiration.

however, need to understand fully whats going on in test_pickled.PickleTest.test_instance_deferred_cols before changing anything.

[Mike Bayer]

consider also:

Index: lib/sqlalchemy/orm/properties.py
===================================================================
--- lib/sqlalchemy/orm/properties.py    (revision 6791)
+++ lib/sqlalchemy/orm/properties.py    (working copy)
@@ -115,7 +115,8 @@
                 impl = dest_state.get_impl(self.key)
                 impl.set(dest_state, dest_dict, value, None)
         else:
-            dest_state.expire_attributes(dest_dict, [self.key](self.key))
+            if self.key not in dest_dict:
+                dest_state.expire_attributes(dest_dict, [self.key](self.key))

     def get_col_value(self, column, value):
         return value

[Mike Bayer]

733d8e593a611b4601ec2ee197ca112250111b64

[Former user]

This seems fixed for merging objects where the entity already exists in the database.

If the entity is not in the database, however, {{{merge()}}} will create a ''Pending'' instance from the passed ''Transient'' object. With {{{load=True}}}, this ''Pending'' instance should not have expired attributes, since it was just loaded from the database.

The following script illustrates:

from sqlalchemy import *
from sqlalchemy.orm import *

engine = create_engine('postgres://user:pass@localhost:5444/name',echo=True)
metadata = MetaData()
Session = sessionmaker(bind=engine)
session = Session()

order_table = Table("orders", metadata,
    Column("orderid", Unicode, primary_key=True)
)

orderdetail_table = Table("orderdetails",metadata,
    Column("orderid", Unicode, ForeignKey('orders.orderid'), primary_key=True),
    Column("lineid", Integer, primary_key=True),
    Column("saleprice", Numeric, nullable=False)
)

class Order(object):
    pass

class OrderDetail(object):
    pass

order_mapper = mapper(Order, order_table,
        properties=dict(orderdetails=relation(OrderDetail, 
                        cascade='all,delete-orphan', 
                        single_parent=True,
                        lazy=False,
                        backref=backref('parentorder',
                                cascade='refresh-expire,expunge'))))

orderdetail_mapper = mapper(OrderDetail, orderdetail_table,
        allow_partial_pks=False)

o=Order()
o.orderid = u'SALE35426'  # NOT IN THE DATABASE, WILL be added by merge()

line=OrderDetail()      
line.orderid = u'SALE35426' # NOT IN THE DATABASE, WILL be added by merge()
line.lineid = 2

o.orderdetails = [line](line)
merged=session.merge(o)

merged.orderdetails[0](0).saleprice

During the {{{merge()}}} call, if {{{load=True}}} and the entity is not found, it seems to be all attributes should be fully loaded and not expired. However, the getattr on saleprice in the last line shows otherwise:

>>> merged=session.merge(o)
2010-05-03 10:43:54,016 INFO sqlalchemy.engine.base.Engine.0x...af10 select version()
2010-05-03 10:43:54,021 INFO sqlalchemy.engine.base.Engine.0x...af10 {}
2010-05-03 10:43:54,023 INFO sqlalchemy.engine.base.Engine.0x...af10 select current_schema()
2010-05-03 10:43:54,023 INFO sqlalchemy.engine.base.Engine.0x...af10 {}
############ merge() looks up order... doesn't find it ##############
2010-05-03 10:43:54,026 INFO sqlalchemy.engine.base.Engine.0x...af10 BEGIN
2010-05-03 10:43:54,027 INFO sqlalchemy.engine.base.Engine.0x...af10 SELECT
orders.orderid AS orders_orderid, orderdetails_1.orderid AS orderdetails_1_orderid,
orderdetails_1.lineid AS orderdetails_1_lineid, orderdetails_1.saleprice AS 
orderdetails_1_saleprice
FROM orders LEFT OUTER JOIN orderdetails AS orderdetails_1 ON orders.orderid = orderdetails_1.orderid
WHERE orders.orderid = %(param_1)s
2010-05-03 10:43:54,027 INFO sqlalchemy.engine.base.Engine.0x...af10 {'param_1': u'SALE35426'}
############ merge() looks up orderdetail... doesn't find it ##############
2010-05-03 10:43:54,033 INFO sqlalchemy.engine.base.Engine.0x...af10 SELECT 
orderdetails.orderid AS orderdetails_orderid, orderdetails.lineid AS 
orderdetails_lineid, orderdetails.saleprice AS orderdetails_saleprice
FROM orderdetails
WHERE orderdetails.orderid = %(param_1)s AND orderdetails.lineid = %(param_2)s
2010-05-03 10:43:54,033 INFO sqlalchemy.engine.base.Engine.0x...af10 {'param_1': u'SALE35426', 'param_2': 2}
>>>
############ since it was just 'loaded' from the database, (not found)
############ no attributes should be expired, should they?
>>> merged.orderdetails[0](0).saleprice
2010-05-03 10:43:54,035 INFO sqlalchemy.engine.base.Engine.0x...af10 SELECT orderdetails.saleprice AS orderdetails_saleprice
FROM orderdetails
WHERE orderdetails.orderid = %(param_1)s AND orderdetails.lineid = %(param_2)s
2010-05-03 10:43:54,036 INFO sqlalchemy.engine.base.Engine.0x...af10 {'param_1': u'SALE35426', 'param_2': 2}
>>>

Functionally, nothing is wrong, but this would be a nice performance enhancement.

P.S. Please add [e-mail] to cc: if you do something with this or if you open another ticket. How do I go about getting a trac user id?

[Mike Bayer]

added #1789

[Mike Bayer]

Removing milestone: 0.6.0 (automated comment)