Thanks for everything. On 5 oct, 16:39, Michael Bayer <mike...@zzzcomputing.com> wrote: > On Oct 5, 2011, at 2:58 AM, rdunklau wrote: > > > > >> the correct value "t_id" is returned. > > > I ran this exact same test on my postgresql 9.1.1 install, and it > > fails. > > OK then its a PG 9 thing. We had an almost identical issue involving indexes > and this is likely the same thing, this bug can be tracked > athttp://www.sqlalchemy.org/trac/ticket/2291. > > For the moment which you can work around with the manual Column. > > > > > > > > > > >> we used information_schema many years ago. At least back then, its > >> performance was orders of magnitude slower and it also does not return > >> complete data. > >> The information schema views are extremely slow for big reflection jobs. > >> The PG tables also have information on PG specific features, which we need > >> to get at: > > >> "The information schema views do not, however, contain information about > >> PostgreSQL-specific features; to inquire about those you need to query the > >> system catalogs or other PostgreSQL-specific views. " > > >> Most articles/howtos/help/documentation I've ever seen on the subject use > >> the pg_ tables, some examples: > > >>http://crafted-software.blogspot.com/2011/03/get-all-column-names-of-...using > >> both INFO_SCHEMA and pg_ tables) > > >> I've also analyzed the queries emitted by the pgAdmin3 tool and it uses > >> the pg_ tables. We've had lots of bugs with PG reflection and the system > >> tables have always ultimately had the right information, though sometimes > >> very hard to get at. > > > Thank you for this comprehensive explanation. > > >>> Does anyone have any workaround (besides the obvious: remap the table > >>> manually) ? > > >> SQLAlchemy can attempt to work around the issue if a known workaround for > >> the PG version in question is present, or alternatively you can provide > >> the primary key column of the Table manually using the technique described > >> athttp://www.sqlalchemy.org/docs/core/schema.html#overriding-reflected-.... > > > I'll try that. > > > -- > > Ronan Dunklau
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