“Adapter does not support geometry” exception when

问题:

In my application, an "Adapter does not support geometry" exception is being thrown when attempting to create a field of type, "geometry()". For my test application, I'm using an sqlite DB (production will use postgres):

db = DAL('sqlite://storage.sqlite', pool_size = 1, fake_migrate_all= False)

The DB table in question is declared within a class, inside of a module, and contains a several fields, some of which contain location data:

from gluon.dal import Field, geoPoint, geoLine, geoPolygon

class Info(Base_Model):

    def __init__(...):

        try: 
            db.define_table('t_info', 
                ...
                Field('f_geolocation', type='geometry()', 
                    label =  current.T('Geolocation')),
                Field('f_city', type='string', 
                    label = current.T('City')),
                ...
        except Exception as e:
            ...

Edit:

As per Anthony's suggestion, I've modified the DAL constructor call to the following:

db = DAL('spatialite://storage.sqlite', pool_size = 1)

It produces the following error message:

Traceback (most recent call last):
  File "C:\...\web2py\gluon\restricted.py", line 227, in restricted
    exec ccode in environment
  File "C:/My_Stuff/Programs/web2py/applications/Proj/models/db.py", line 38, in <module>
    db = DAL('spatialite://storage.sqlite', pool_size = 1) 
  File "C:\...\web2py\gluon\packages\dal\pydal\base.py", line 171, in __call__
    obj = super(MetaDAL, cls).__call__(*args, **kwargs)
  File "C:\...\web2py\gluon\packages\dal\pydal\base.py", line 457, in __init__
    raise RuntimeError("Failure to connect, tried %d times:\n%s" % (attempts, tb))
RuntimeError: Failure to connect, tried 5 times:
Traceback (most recent call last):
  File "C:\...\web2py\gluon\packages\dal\pydal\base.py", line 435, in __init__
    self._adapter = ADAPTERS[self._dbname](**kwargs)
  File "C:\...\web2py\gluon\packages\dal\pydal\adapters\base.py", line 53, in __call__
    obj = super(AdapterMeta, cls).__call__(*args, **kwargs)
  File "C:\...\web2py\gluon\packages\dal\pydal\adapters\sqlite.py", line 169, in __init__
    if do_connect: self.reconnect()
  File "C:\...\web2py\gluon\packages\dal\pydal\connection.py", line 129, in reconnect
    self.after_connection_hook()
  File "C:\...\web2py\gluon\packages\dal\pydal\connection.py", line 81, in after_connection_hook
    self.after_connection()
  File "C:\...\web2py\gluon\packages\dal\pydal\adapters\sqlite.py", line 177, in after_connection
    self.execute(r'SELECT load_extension("%s");' % libspatialite)
  File "C:\...\web2py\gluon\packages\dal\pydal\adapters\base.py", line 1326, in execute
    return self.log_execute(*a, **b)
  File "C:\...\web2py\gluon\packages\dal\pydal\adapters\base.py", line 1320, in log_execute
    ret = self.cursor.execute(command, *a[1:], **b)
OperationalError: The specified module could not be found.

回答1:

If you want to use geometry fields with SQLite, you must use the spatialite adapter, which makes use of the SpatialLite extension for SQLite:

db = DAL('spatialite://storage.sqlite', pool_size = 1)

Note, you must have spatialite installed for this to work.