[sqlalchemy] can a SqlAlchemy session be extracted from an object ?
i'm trying to deal with some old code , and need to 'log' a change. in the current code block, I do not have a SqlAlchemy session object - i merely have an ORM object that exists in a given session. is it possible to extract the session object from that ORM object, so I can just add a new ORM object to it? doing the correct thing, and getting the session object into the code block properly will take more time than I have right now. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sqlalchemy] can a SqlAlchemy session be extracted from an object ?
Yep: object_session(obj) http://docs.sqlalchemy.org/en/rel_0_8/orm/session.html#sqlalchemy.orm.session.Session.object_session Regards, Gulli On Thu, May 2, 2013 at 4:47 PM, Jonathan Vanasco jonat...@findmeon.comwrote: i'm trying to deal with some old code , and need to 'log' a change. in the current code block, I do not have a SqlAlchemy session object - i merely have an ORM object that exists in a given session. is it possible to extract the session object from that ORM object, so I can just add a new ORM object to it? doing the correct thing, and getting the session object into the code block properly will take more time than I have right now. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sqlalchemy] can a SqlAlchemy session be extracted from an object ?
and in 0.8 its this: from sqlalchemy import inspect session = inspect(obj).session On May 2, 2013, at 12:50 PM, Gunnlaugur Thor Briem gunnlau...@gmail.com wrote: Yep: object_session(obj) http://docs.sqlalchemy.org/en/rel_0_8/orm/session.html#sqlalchemy.orm.session.Session.object_session Regards, Gulli On Thu, May 2, 2013 at 4:47 PM, Jonathan Vanasco jonat...@findmeon.com wrote: i'm trying to deal with some old code , and need to 'log' a change. in the current code block, I do not have a SqlAlchemy session object - i merely have an ORM object that exists in a given session. is it possible to extract the session object from that ORM object, so I can just add a new ORM object to it? doing the correct thing, and getting the session object into the code block properly will take more time than I have right now. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sqlalchemy] can a SqlAlchemy session be extracted from an object ?
On Thu, May 2, 2013 at 5:08 PM, Michael Bayer mike...@zzzcomputing.comwrote: and in 0.8 its this: from sqlalchemy import inspect session = inspect(obj).session Is this preferred over object_session in 0.8? object_session is still there, and docs don't say it's deprecated or that inspect(obj).session is preferred. Gulli -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sqlalchemy] can a SqlAlchemy session be extracted from an object ?
ultimately I'm hoping the inspect() system is just easier for everyone, but I haven't deprecated the old functions. I doubt I'd ever remove them at this point, and they are still used internally since there's a tad less overhead to them. On May 2, 2013, at 1:31 PM, Gunnlaugur Thor Briem gunnlau...@gmail.com wrote: On Thu, May 2, 2013 at 5:08 PM, Michael Bayer mike...@zzzcomputing.com wrote: and in 0.8 its this: from sqlalchemy import inspect session = inspect(obj).session Is this preferred over object_session in 0.8? object_session is still there, and docs don't say it's deprecated or that inspect(obj).session is preferred. Gulli -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sqlalchemy] Are sqlalchemy queries a generator?
On Fri, Apr 26, 2013 at 8:59 PM, Michael Bayer mike...@zzzcomputing.com wrote: All attributes have to be expire-able and act as proxies for a database connection so I'm not really sure where to go with that.I'm not too thrilled about proposals to build in various alternate performance behaviors as the library starts to try to act in many different ways that the vast majority of users aren't even aware of, it increases complexity internally, produces vast amounts of new use cases to test and maintain, etc.I'm always willing to look at patches that are all winning, of course, so if you have some way to speed things up without breaking usage contracts and without major new complexity/brittleness I'd love to look at a pull request. I know, it's just a probe to see what kind of a speedup could be obtained by not having that getter's interference. You know... simply implementing InstrumentedAttribute in C could do the trick... In fact... I'm gonna try that... feel free! though you might be surprised, a C function that just calls out to all the same Python operations anyway is often only negligibly faster, not enough to make the extra complexity worth it. Ok, I got around to profiling this. The C extension saves 20s from 800s, as noted before, most of those 800s are SA-unrelated application logic, and the app has been greatly optimized to avoid attribute access, so average speedup would most likely be far more. As expected, the getter disappears from profiles (it's seen as the calling function's time now). I've got a function that makes some unavoidable access to instrumented attributes. It's get_params, it's called around 7M times, so while small, the overhead does add up. I made sure expiration works btw. Without the C extension: ncalls tottime percall cumtime percall filename:lineno(function) 20811734 27.8290.000 27.8550.000 attributes.py:171(__get__) 7631984 13.5320.000 31.8510.000 ruby.py:86(get_param) With the C extension: ncalls tottime percall cumtime percall filename:lineno(function) 7631984 19.5140.000 21.0510.000 ruby.py:86(get_param) Notice how the C extension saves a total of 10s (cumtime, sum of internal and external time). There's no DB access when hitting those arguments, as everything has been eagerly loaded. It's all function call overhead. Assuming an application makes heavy use of attributes, as get_param does (expectable of straightforward code I'd think), that's a 30% speedup of CPU-bound code. As soon as I get GC right I'll post the patch. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sqlalchemy] Tricky situation
Thank you Mariano. I tested your solution, but it didn't work as well as your previous one - since I use a lot of self referential, polymorphic entities; they may not like union_all :-( But it does provides a simplier approach if you're not using it the way I do :) Thanks again! Best regards, Richard. On 04/29/2013 02:57 PM, Mariano Mara wrote: On 04/25/2013 11:17 AM, Richard Gerd Kuesters wrote: Well. I'm pretty interested :) I did find your solution very flexible, thou. Thanks a lot, Richard. For completeness, here is a pure sqlalchemy version of the same recursive ideas: def _hierarchy(): # TODO: check if object has self referential key sq1 = S.query(self.model) sq1 = sq1.add_columns(*(label(level, literal(1, type_=Integer)), label(cycle, literal(False, type_=Boolean)), label(connect_path, literal_column(ARRAY[id], ARRAY(Integer) sq1 = sq1.filter(self.model.parent_id==None) sq1 = sq1.cte(name=sq1, recursive=True) sq1_alias = aliased(sq1, name=pr) sq2_alias = aliased(self.model, name=p) sq1 = sq1.union_all( S.query(sq2_alias, label(level, sq1_alias.c.level+1), label(cycle, Any(sq2_alias.id, sq1_alias.c.connect_path)), label(connect_path, func.array_append(sq1_alias.c.connect_path, sq2_alias.id)) ).filter(and_(sq2_alias.parent_id==sq1_alias.c.id, ~sq1_alias.c.cycle))) q = S.query(sq1) q = q.add_columns(*(label(is_leaf, case([( sq1.c.connect_path.contained_by( over(func.lead( sq1.c.connect_path, 1),order_by=sq1.c.connect_path))==True, False)], else_=True)),)) return q.all() It could use some testing (something I am about to do) and you still need to cast to your object but all the ingredients are here. As usual the model needs a self referential key (in this case id and parent_id). I try not to use the textual ARRAY[id] to generate the first connect_path but I couldn't make it without errors (and the time was pressing): If you have a suggestion on how to do so, I will surely appreciate it. Mariano On 04/25/2013 11:08 AM, Mariano Mara wrote: On 04/25/2013 10:22 AM, Richard Gerd Kuesters wrote: Hi all, I've been playing with sqla_hierarchy from https://github.com/marplatense/sqla_hierarchy . That code of that sqla_hierarchy was written to provide a limited support for cte, from the time when sqalchemy didn't have cte. Since sqlalchemy has cte now I would recommend to migrate to pure sqlalchemy code which will open more possibilities for you to interact with your objects and provide support in the long term. I am currently trying to do so (and once I solve how to get *level*, *is_leaf* and *connect_path* attributes as part of the results, I can surely share it through the list for anyone who's interested). Mariano -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
[sqlalchemy] Re: can a SqlAlchemy session be extracted from an object ?
this is WONDERFUL. thanks! On Thursday, May 2, 2013 12:47:25 PM UTC-4, Jonathan Vanasco wrote: i'm trying to deal with some old code , and need to 'log' a change. in the current code block, I do not have a SqlAlchemy session object - i merely have an ORM object that exists in a given session. is it possible to extract the session object from that ORM object, so I can just add a new ORM object to it? doing the correct thing, and getting the session object into the code block properly will take more time than I have right now. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
[sqlalchemy] Using UniqueConstraint or unique=True
I am trying to ensure that my table doesn't allow duplicate rows.
The table is defined (in SqlAlchemy 0.8):
class User(Base):
__tablename__ = 'user'
id = Column(Integer, primary_key=True)
lname = Column(String)
fname = Column(String)
email = Column(String)
dateentered = Column(DateTime, default=datetime.now())
UniqueConstraint('lname','fname',name='full_name')
~ etc.
I have tried with using the above and with adding the unique constraint
to the relevant field definitions. Using the unique constraint on
individual fields makes a table that requires both the lname and the
fname field to be unique. Using the code above there seems to be no
constraints whatsoever, a session.commit() simply adds the duplicate
rows. What I am going for is something like this (using an sqlite3
database):
CREATE TABLE user (lname string, fname string, email string,
unique(lname, fname) ON CONFLICT REPLACE);
This will allow me to add multiple rows with the same lname as long as
the fnames are different for each. Is there a way to define such unique
constraints in SqlAlchemy?
thomas
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