change again, that doesn't work. Upon reflection, I think the case here is that there's no alternative but to make sure psycopg2 can properly format the contents of the ARRAY itself. This is because SQLAlchemy is producing a completed INSERT statement for preparation, without the parameters actually filled in:
INSERT INTO table (x) VALUES (%(x)s) At that point, SQLAlchemy is done producing strings, and sends it off to psycopg2 along with an array value for "x". So there is no opportunity here for a user-defined bind expression generator to further modify the expression above. More fundamentally, the above statement can be called using DBAPI executemany(); each value for "x" can be an array of a *different* length. So it's totally up to psycopg2 here to handle this case, and it even suggests that prepared statements can't be used very effectively with Postgresql ARRAY types (psycopg2 doesn't use prepared statements AFAIK). On Jan 7, 2013, at 9:58 AM, Michael Bayer wrote: > correction, this seems to work, though will try to improve: > > class UUID_ARRAY(TypeDecorator): > impl = ARRAY(UUID, dimensions=1) > > def bind_expression(self, bindvalue): > if bindvalue.callable: > val = bindvalue.callable() > else: > val = bindvalue.value > if val is None: > val = [] > elif not hasattr(val, '__iter__'): > return bindvalue > return array( > cast(literal(str(uuid_val)), UUID()) > for uuid_val in val > ) > > > > On Jan 7, 2013, at 9:55 AM, Michael Bayer wrote: > >> this is ticket http://www.sqlalchemy.org/trac/ticket/2648 and cannot be >> worked around at this time. If you're working with arrays of UUID I'd >> recommend using psycopg2 type processors, as the previous poster has had >> success with. >> >> >> >> On Jan 7, 2013, at 9:39 AM, Hans Lellelid wrote: >> >>> I am looking to adapt this code for a related array/type issue. The code >>> from https://gist.github.com/4433940 works just fine for me (as expected) >>> when building/executing the stmt directly, but not when using the ORM. >>> >>> When row is created using ORM, like this: >>> >>> # <snip> >>> s = Session(bind=engine) >>> e = Example() >>> e.timestamp=datetime.datetime.utcnow(), >>> e.num=2, >>> e.guids = [uuid.uuid4(), uuid.uuid4()] >>> s.add(e) >>> s.commit() >>> >>> I get an error like this: >>> >>> <snip> >>> return getter(visitor)(self, **kw) >>> File >>> "/home/hans/workspace/providence/env/lib/python2.7/site-packages/SQLAlchemy-0.8.0b2-py2.7-linux-x86_64.egg/sqlalchemy/sql/compiler.py", >>> line 760, in visit_bindparam >>> bind_expression = bindparam.type.bind_expression(bindparam) >>> File "test_array.py", line 38, in bind_expression >>> for uuid_val in val >>> TypeError: 'object' object is not iterable >>> >>> (I can dump in full stack if that would be helpful.) >>> >>> Indeed, inspecting that reveals that it is simply an object() instance. >>> I'm not sure where that is being set or whether there is an obvious >>> workaround here. I'm sure I'm simply missing obvious when it comes to >>> dealing with native array types and ORM entity instances. >>> >>> Thanks, >>> Hans >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "sqlalchemy" group. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msg/sqlalchemy/-/ZwxFp2iasq0J. >>> To post to this group, send email to sqlalchemy@googlegroups.com. >>> To unsubscribe from this group, send email to >>> sqlalchemy+unsubscr...@googlegroups.com. >>> For more options, visit this group at >>> http://groups.google.com/group/sqlalchemy?hl=en. >> >> >> -- >> 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 >> sqlalchemy+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/sqlalchemy?hl=en. > > > -- > 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 > sqlalchemy+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/sqlalchemy?hl=en. -- 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 sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
