thanks for this complete answer ! I will investigate a little more in existing projects like geoalchemy, mapfish to find a nice way to implement oracle spatial support.
regards Nicolas 2009/9/7 Sanjiv Singh <singhsanj...@gmail.com> > > On Mon, Sep 7, 2009 at 8:25 PM, Michael Bayer<mike...@zzzcomputing.com> > wrote: > > > > SQL expressions can't be called from within the bind processor of > > types. The bind processor only affects the values sent as parameters > > to the DBAPI execute() and executemany() functions. There is a > > feature request that is as yet unimplemented to provide this feature, > > however. > > > > An approach towards embedding geometry functions has been addressed in > > a SQLAlchemy example which you can find in the source distribution in > > examples/postgis/ . This example builds upon the ORM to provide the > > embedding so might not work for your needs. > > > > A full blown package for GIS integration is GeoAlchemy: > http://geoalchemy.org/ > > , which supports three different spatial databases. Oracle's > > backend could be added to this package as well if you were in it for > > the long haul and could contribute to them. I am not entirely > > certain but I think this package may be building off of the examples > > in the Postgis example. > > Absolutely. It has been acknowledged here[1] :) > > The code could be improved a lot as has been discussed here earlier[2] > but I have not yet had the time for that. > I would be happy to see some participation. So please feel free to > clone the repo[3] and send pull requests. > > regards > Sanjiv > > [1] http://geoalchemy.org/intro.html#author > [2] > http://groups.google.com/group/sqlalchemy/browse_thread/thread/b84682489891563e# > [3] http://bitbucket.org/sanjiv/geoalchemy/ > > > > > Here's yet another approach which uses the compiler extension. This > > is at the SQL level and may be enough to suit your needs, and also > > adds bind parameter support to your function. It requires the usage > > of a custom SQL element for the "value" side of an expression (it is > > essentially a more explicit version of how the aforementioned feature > > improvement would be implemented): > > > > from sqlalchemy import * > > from sqlalchemy.sql import ClauseElement, table, column > > from sqlalchemy.ext.compiler import compiles > > > > m = MetaData() > > > > t = table('mytable', > > column('some_geom') > > ) > > > > class GeomValue(ClauseElement): > > def __init__(self, wkt, srid): > > self.wkt = literal(wkt) > > self.srid = srid > > > > @compiles(GeomValue) > > def compile_geom(element, compiler, **kw): > > return "SDO_GEOMETRY(%s,%s)" % (compiler.process(element.wkt), > > element.srid) > > > > > > print t.insert().values(some_geom=GeomValue("foo", "bar")) > > > > print t.select().where(t.c.some_geom==GeomValue("foo", "bar")) > > > > > > > > On Sep 7, 2009, at 7:39 AM, Nicolas wrote: > > > >> > >> Hi list, > >> > >> While trying to build a type for spatial geometry in Oracle Spatial > >> ( SDO_GEOMETRY) , i try to use the build-in function SDO_GEOMETRY from > >> oracle in the bind_processor for converting WKT (text representation > >> for spatial geometry) to SDO_GEOM. > >> > >> The problem is that sqlalchemy place quotes around the SDO_GEOMETRY > >> function call and then i have the following error : > >> > >> DatabaseError: (DatabaseError) ORA-00932: inconsistent datatypes: > >> expected MDSYS.SDO_GEOMETRY got CHAR > >> > >> I there a way to call functions in the bind_processor ??? > >> > >> Sample code : > >> > >> def bind_processor(self, dialect): > >> """convert value from a geometry object to database""" > >> def convert(value): > >> if value is None: > >> return None > >> else: > >> ------> return "SDO_GEOMETRY('%s',%s)" % (value.wkt, self.srid) > >> > >> return convert > >> > >> def result_processor(self, dialect): > >> """convert value from database to a geometry object""" > >> def convert(value): > >> if value is None: > >> return None > >> else: > >> return asShape(sdo.Geometry(value)) > >> > >> return convert > >> > >> > > > > > > > > > > > > > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
