Yup, that did it. Many thanks, Alex!
On Tuesday, August 27, 2013 5:34:03 PM UTC-4, Alex wrote:
>
> my mistake, the alias should be for table location.
>
> location_one = db.location.with_alias('location_one')
> location_two = db.location.with_alias('location_two')
>
>
> I hope this works.
>
> Am Dienstag, 27. August 2013 21:51:56 UTC+2 schrieb Apple Mason:
>>
>> Hey Alex,
>>
>> Thanks for the suggestion. The problem with the query is that
>> 'location_one.geom.st_equals(point_x_y)' won't work. That's because the
>> table db.item_location doesn't have a field called 'geom'. This is the
>> error:
>>
>> AttributeError: 'Table' object has no attribute 'geom'
>>
>>
>> Is there a way to implicitly reference the fields in another table so
>> that it will work?
>>
>> On Tuesday, August 27, 2013 3:15:10 PM UTC-4, Alex wrote:
>>>
>>> try something like this:
>>>
>>>
>>> location_one = db.item_location.with_alias('location_one')
>>> location_two = db.item_location.with_alias('location_two')
>>> rows = db((db.item_location.item == db.item.id) & (db.item.id != itemid)
>>> & (db.item_location.location_one == location_one.id) & (db.item_location
>>> .location_two == location_two.id) &
>>> (location_one.geom.st_equals(point_x_y)) & (location_two.geom.
>>> st_equals(point_n_m))).select(db.item.ALL)
>>>
>>> Alex
>>>
>>> Am Dienstag, 27. August 2013 19:43:08 UTC+2 schrieb Apple Mason:
>>>>
>>>> I have this many to many relationship example:
>>>>
>>>> db.define_table('location',
>>>> Field('geom', 'geometry()'))
>>>>
>>>> db.define_table('item',
>>>> Field('name'))
>>>>
>>>> db.define_table('item_location',
>>>> Field('item', db.item),
>>>> Field('location_one', db.location),
>>>> Field('location_two', db.location))
>>>>
>>>>
>>>>
>>>> The goal is to find all items that are NOT the given item.id, but
>>>> matches locations.
>>>> An example query would be:
>>>>
>>>> Given: item.id==1 and two points POINT(x,y) and POINT(n,m),
>>>> Result: "get all items that are not item.id==1, but has
>>>> location_one==POINT(x,y) and location_two==POINT(n,m)"
>>>>
>>>> I am able to get it matching one of the points, but not the other with
>>>> this:
>>>>
>>>>
>>>> point_x_y = "POINT(1,2)"
>>>> point_n_m = "POINT(3,4)"
>>>> itemid = 1
>>>>
>>>> t = db( (db.item.id==db.item_location.item) &
>>>> ( (db.location.id==db.item_location.location_one) & (db.
>>>> location.geom.st_equals(point_x_y))))
>>>>
>>>> result = t( db.item.id != itemid ).select()
>>>>
>>>>
>>>> This will successfully match all items that do not have an id=1, and
>>>> has location_one as point_x_y.
>>>>
>>>> The problem is I do not know how to match location_two with point_n_m.
>>>> I tried this, but it doesn't make sense (it also returns in nothing):
>>>>
>>>> t = db( (db.item.id==db.item_location.item) &
>>>> ( (db.location.id==db.item_location.location_one) & (db.
>>>> location.geom.st_equals(point_x_y)))
>>>> ( (db.location.id==db.item_location.location_two) & (db.
>>>> location.geom.st_equals(point_n_m))))
>>>>
>>>> Any help would be great!
>>>>
>>>
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