[sqlalchemy] Re: Temporary Disable Session.mapper with Scoping
On Thu, 15 Nov 2007 10:09:08 -0500, Michael Bayer [EMAIL PROTECTED] wrote: [On Session.mapper] it would be easier if you just didnt use autosave, id really love to remove that feature entirely. IMO removing that functionality would make SQLAlchemy a lot more awkward to use. /me votes for keeping it in. -- Gerhard --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] path based options and contains_eager
I noticed that the path_based_options branch has been merged, which
looks great as a way to eager-load deep relationships in queries built
with from statements (ie: query.from_statement). I noticed some
strange behavior and I want to check that I've got the right idea
before I open any tickets:
Both of them come from using contains_eager with a path. After setting
up a mapping similar to the AdjacencyTree example in trunk I'm joining
to the same table twice with aliases like this (This doesn't really
show why I'm doing this in the first place, but it should illustrate
the problem):
ali = trees.alias()
ali2 = trees.alias()
statement = trees.outerjoin(ali, trees.c.node_id==ali.c.parent_node_id)
statement = statement.outerjoin(ali2, ali.c.node_id==ali2.c.parent_node_id)
statement =
statement.select(use_labels=True).where(trees.c.parent_node_id==None)
query = create_session().query(TreeNode).from_statement(statement)
So I have a query created from the statement, which should be the
table joined to itself twice. Now if I set two contains_eager options
using the new path behaviour:
root = query.options(contains_eager('children'),
contains_eager('children.children')).one()
(Pdb) root.children
{u'rootnode': rootnode (1,None, 139201708)
}
(Pdb) root.children['rootnode'].children
{u'rootnode': rootnode (1,None, 139201708)
}
(Pdb) root.children['rootnode'].children['rootnode'].children
{u'rootnode': rootnode (1,None, 139201708)
}
This looks like root thinks that it is it's own child. It might be
that I need to use an alias with the contains_eager option, but if I
do:
root = query.options(contains_eager('children', alias=ali),
contains_eager('children.children', alias=ali2)).one()
Traceback (most recent call last):
File basic_tree.py, line 88, in module
root = query.options(contains_eager('children', alias=ali),
contains_eager('children.children', alias=ali2)).one()
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/query.py,
line 641, in one
ret = list(self[0:2])
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/query.py,
line 655, in __iter__
return self._execute_and_instances(context)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/query.py,
line 660, in _execute_and_instances
return iter(self.instances(result, querycontext=querycontext))
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/query.py,
line 721, in instances
self.select_mapper._instance(context, row, result)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/mapper.py,
line 1448, in _instance
self.populate_instance(context, instance, row, **flags)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/mapper.py,
line 1514, in populate_instance
(newpop, existingpop, post_proc) =
selectcontext.exec_with_path(self, prop.key,
prop.create_row_processor, selectcontext, self, row)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/query.py,
line 1223, in exec_with_path
return func(*args, **kwargs)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/interfaces.py,
line 487, in create_row_processor
return
self._get_context_strategy(selectcontext).create_row_processor(selectcontext,
mapper, row)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/strategies.py,
line 593, in create_row_processor
row_decorator = self._create_row_decorator(selectcontext, row,
selectcontext.path)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/strategies.py,
line 580, in _create_row_decorator
decorated_row = decorator(row)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/strategies.py,
line 709, in decorate
for c in prop.target.columns:
NameError: free variable 'prop' referenced before assignment in enclosing scope
So without aliases there is a cycle, but with aliases there's this
exception. Just for kicks I tried using the name of the alias instead
of the alias object:
root = query.options(contains_eager('children', alias=ali.name),
contains_eager('children.children', alias=ali2.name)).one()
Traceback (most recent call last):
File basic_tree.py, line 88, in module
root = query.options(contains_eager('children', alias=ali.name),
contains_eager('children.children', alias=ali2.name)).one()
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/query.py,
line 267, in options
opt.process_query(q)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/interfaces.py,
line 561, in process_query
self.process_query_property(query, paths)
File /home/stephen/src/sqlalchemy/lib/sqlalchemy/orm/strategies.py,
line 704, in process_query_property
(mapper, propname) = paths[-1]
ValueError: too many values to unpack
and I get a different exception.
I'm a bit confused now, so please tell me if I've got something
fundamentally wrong here, otherwise are these bugs?
Thanks
Stephen Emslie
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[sqlalchemy] sqlalchemy and postgresql warning messages
Hi.
I have found an insidious problem with SQLAlchemy and PostreSQL.
Here is an example:
from sqlalchemy import engine, schema, sql, types
metadata = schema.MetaData()
a = schema.Table(
'a', metadata,
schema.Column('id', types.Integer, primary_key=True),
schema.Column('x', types.Integer),
)
b = schema.Table(
'b', metadata,
schema.Column('id', types.String, schema.ForeignKey(a.c.id),
primary_key=True),
schema.Column('y', types.Integer),
)
URL = 'postgres://twisted_test:[EMAIL PROTECTED]/twisted_test'
db = engine.create_engine(URL, echo=True)
metadata.bind = db
try:
metadata.create_all()
finally:
metadata.drop_all()
There is an error in the schema, b.id is of type String instead of type
Integer.
Unfortunately PostgreSQL does not raises an error, but just a warning.
In fact I have found such a problem in one of my programs only after a
pg_dump + pg_restore:
WARNING: foreign key constraint b_id_fkey will require costly
sequential scans
DETAIL: Key columns id and id are of different types: text and integer.
What's the best method to avoid these bugs?
It would be nice to have something like `salint`, that can scan a
metadata searching for problems.
Also, it would help if PostgreSQL warnings messages can be reported by
psycopg/SQLAlchemy.
Better if warnings can be considered like errors, thus raising an
exception (something like the Werror option in GCC).
Thanks Manlio Perillo
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[sqlalchemy] Re: sqlalchemy and postgresql warning messages
On Nov 16, 2007, at 1:54 PM, Manlio Perillo wrote: There is an error in the schema, b.id is of type String instead of type Integer. Unfortunately PostgreSQL does not raises an error, but just a warning. In fact I have found such a problem in one of my programs only after a pg_dump + pg_restore: WARNING: foreign key constraint b_id_fkey will require costly sequential scans DETAIL: Key columns id and id are of different types: text and integer. What's the best method to avoid these bugs? It would be nice to have something like `salint`, that can scan a metadata searching for problems. Also, it would help if PostgreSQL warnings messages can be reported by psycopg/SQLAlchemy. Better if warnings can be considered like errors, thus raising an exception (something like the Werror option in GCC). if the warning is issued by Psycopg2, you can turn warnings into exceptions using the warnings filter, http://www.python.org/doc/lib/warning-filter.html . If its not, then SA can't do anything about it, you'd have to post on the psycopg2 list for this behavior to be supported. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: Oracle date/datetime oddities
On Nov 15, 2007 1:43 PM, Michael Bayer [EMAIL PROTECTED] wrote: yes, this was in my previous email: We might look into changing that to an OracleDateTime for autoload=True on the next release. In the meantime, override your reflected DATE column with an OracleDateTime type. though we dont have any 0.3 releases planned in the near future, we'll probably get it into 0.4.1 . I was just responding to the we might look into changing it part, and trying to give evidence that it's a real problem. I'm contemplating upgrading to 0.4, in which case I'll submit a (trivial) patch for this. Thanks for looking at this problem! Eric. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Can I remove a Column from the select() result set
Howdy Group, Let's say I have a very simple query: select person.id, person.name, person.age from person Can I remove one of the columns, say person.age, from this result set and still use the list as a RowProxy? I'm trying to do it now and it's not working. I'm creating a new list and appending all but the last (for example) columns, but it's then missing the RowProxy goodness. I realize I can do this in the original select, but I'm doing some client-side logic here and I need to manipulate the dataset. Thanks, Matt --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
