[sqlalchemy] sqlalchemy introspection How?
I have tables created using another orm. I just want to know, how I can create sqlalchemy classes based on the tables, that are already there in the database? Thank you --~--~-~--~~~---~--~~ 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: MemoryError in unitofwork.py
Okay - next dump quesion: How do I clear out the objects in a session that I no longer need to reference (in this case all of them)... Will python GC take care of this? --Brandon On Apr 25, 7:15 am, Michael Bayer [EMAIL PROTECTED] wrote: On Apr 24, 2007, at 10:59 AM,BrandonGoldfedder wrote: I'm doing a fair number of session flushes as I update my data in the database. After about 53 of them (or so) I am getting the following exception: File build\bdist.win32\egg\sqlalchemy\orm\session.py, line 294, in flush File build\bdist.win32\egg\sqlalchemy\orm\unitofwork.py, line 181, in flush MemoryError Anyone have any ideas: My code is simply adding new entries and every 1000 entries flushing the objectstore. the session doesnt clear itself out after a flush, so with each successive save() of objects memory will grow. --~--~-~--~~~---~--~~ 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: SQLAlch. + ODBC + DBISAM... :-(
I'd be happy to host a buildslave here on a VM. AFAIK, the buildslaves connect outbound to the master, which would work for me. As far as hosting the master, I dunno -- we're out here in the hinterlands of Connecticut in dynamic IP address land for now. On 4/27/07, Michael Bayer [EMAIL PROTECTED] wrote: On Apr 26, 2007, at 6:31 PM, Rick Morrison wrote: Sounds like a great idea -- is there an existing buildbot master to tie into, or will the whole thing be new? well my limited understanding of buildbots says that we would need to make one that responds to SQLAlchemy version changes, since the main one at pybots.org responds only to Python builds ? also it requires a persistent running service that is always connected to the master (which i feel is overkill), but we'd have to determine hosting for the whole thing. --~--~-~--~~~---~--~~ 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: Multiple inheritance and relations
On Apr 27, 2007, at 11:17 AM, Dave Harrison wrote:
Hi all,
I've got a situation where I have a table of data that is common,
with the
subtables just adding an extra couple of fields. Using multiple
inheritance I
fit it together as below (pretty much the same as the documented
example).
What I'm having problems with is then accessing those child tables
as properties
of the person table mapping. I'm get the following error,
Cant determine relation direction for 'example' on mapper 'Mapper|
Person|person'
with primary join 'person.id = example.person_id' - foreign key
columns are not
present in neither the parent nor the child's mapped
tablesset([Column('person_id',Integer(),ForeignKey('person.id'))])
the surprise here is that you established the relationship to the
subclass, when the join condition is expressed in the superclass'
table. theres all kinds of logic that is limiting the search for
joins and foreign key relationships to between just the local
tables (i.e. not to the joined inherited/inheriting tables) since we
have a lot of test cases with very intricate self-referential
relationships that blow up easily. so this innocent example led to
the need to make all those searches look in both places separately
and pick the one that fits better. this is in r2564.
P.S that error should read foreign key columns are present in
neither ...
also in r2564.
--~--~-~--~~~---~--~~
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: Problem with clear_mapper
I can use clear_mappers() because I use mod_python and my mappers are defined during init. Is there any other way I can get this select mapped to my object? non_primary=True (see the docs on mutliple mappers for a class) But that would mean I would define a new non_primary mapper every time, wouldn't it? Is this really a good idea for a server software? Is there maybe a way to update the used table without redefining the mapper? if you are creating all kinds of select() objects from which you want to load instances, simply feed those into query.select() and the appropriate instances will be returned (or use query.instances() with the result of execute()). Thanks, that worked great. Bye, Kevin --~--~-~--~~~---~--~~ 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] SQLAlchemy at OSCON
As I understand it, the schedule is still tentative at this point, but the fact that I'll get to teach a SQLAlchemy tutorial is not. (Like my PyCon tutorial, this will be aimed at those who have not yet used SA.) O'Reilly Open Source Convention 2007 at the Oregon Convention Center in Portland, Oregon, July 23-27: - Tutorial Title: SQLAlchemy: Taming ORM with Python Date: 07/24/2007 Time: 1:30pm to 5:00pm --~--~-~--~~~---~--~~ 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: [Sqlalchemy-users] Objects with just some fields
On 4/27/07, Michael Bayer [EMAIL PROTECTED] wrote: On Apr 27, 2007, at 2:19 PM, Mike Orr wrote: Is it possible to make a mapper class that loads modifies only some fields in a table rather than all the fields, yet still autoloads the fields rather than having hardcoded column types? you want to use a deferred column : http://www.sqlalchemy.org/docs/ adv_datamapping.html#advdatamapping_properties_deferred That puts the burden in the wrong place: (1) I have to list all the undesired columns by name, (2) SQLAlchemy has to go to the trouble of making it a deferred column when I'd prefer it just ignore it entirely. yeah when you map to a select, it treats that like a table, and selects from it so that it can be manipulated similarly. Is it safe to do updates on an object mapped to a select? E.g., _sel = select([... fields ...]) class Foo(object): pass mapper(Foo, _sel) for i in session.query(Foo).select(): i.attr = Value session.flush() What I'd like to do is pass a list of column names to the Table constructor and have it autoload those and ignore the others. I couldn't find an argument for this. oh. well that we haven't done yet. the usual use case is that if you know the names of the columns already, why reflect them ? but yes i understand the advantage of getting the data types and foreign key constraints reflected. this wouldnt be a difficult feature to add. Created ticket #561 suggesting: Table(Foo, meta, autoload_columns=[foo_id, col2, col3]) - Is there a supported way to add/remove fields from a query after it's been constructed? from a select(), it supports adding things. there is append_column (), append_whereclause(), order_by(), etc. this API needs docstrings and probably the names order_by/group_by should be named append_order_by() etc.but you can see the methods listed out in the HTML docstrings on the site (html docs also included with the dist). removing things is not stressed so much since the typical use case is building up a query from a core criterion/selectable, and we have the usual issue about decisions being made based on things being appended, which to support removal would mean a lot of new code (which id welcome, of course !) to support un-making those decisions. .append_column just needs to be documented in the manual. .remove_column would be useful, but it's not that important if it's complicated to implement. (I thought the column list was just a simple list until the query was compiled.) I wasn't suggesting .remove_whereclause or .remove_order_by -- I don't see any point for those, and how would one identify the element to remove anyway? -- Mike Orr [EMAIL PROTECTED] --~--~-~--~~~---~--~~ 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] Using MAX in a relation() without an inner SELECT
Hi,
We've got a CMS model with a revisioned page tree. Our pages have a
revision number and a parent page (it's a self-referential mapper).
One property we'd like to have in our assign_mapper call is a
latest_parent relation -- a property that returns the page with
page_id = parent_id and revision_number = MAX revision_number for that
page_id.
We've isolated our case into a simple example, where our table looks
like this:
pages_table = Table('pages', metadata,
Column('page_id', Integer, primary_key=True),
Column('revision_number', Integer, primary_key=True),
Column('parent_id', Integer, ForeignKey('pages.page_id'),
nullable=True),
)
We got the property working in the following complete example:
http://dpaste.com/hold/9205/
However, the query generated by that relation has 2 SELECTs, and the
result we want is possible with a single, very simple SELECT (using
page_id = 3 as an example):
SELECT *, MAX(pages.revision_number) FROM pages WHERE pages.page_id =
3
...and we can (sort-of) accomplish this in SQLAlchemy with this
select():
select([*, func.max(pages_table.c.revision_number)],
pages_table.c.page_id == 3)
However, that returns the tuple given by dbapi and not an instance of
the mapped class. We also can't figure out how to get this behavior in
a relation(), so that just the above SELECT is executed and not nested
SELECTs (as in the pasted example).
Is there some other kind of MapperProperty besides relation that will
let us do this? Any help is appreciated.
Brian Beck / Adventurer of the First order / www.brianbeck.com
--~--~-~--~~~---~--~~
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
-~--~~~~--~~--~--~---
