sqlobject-discuss

[SQLObject] [newbie] problem with MultipleJoin

[<pa...@su...>]

Hi folks,

I'm stuck ATM wrt sqlobject and MultipleJoin. My classes:

class CaCert(CertItem):
    SignedCaCerts = MultipleJoin('SubCaCert')
    ...

class SubCaCert(CertItem):
    Ca = ForeignKey('CaCert')
    ...

class EmailSubCa(SubCaCert):
    SignedCerts = MultipleJoin('EmailCert')
    _table = "sub_ca_cert"
    ...

----test test test-----
rootca = CaCert.new(**rootca_params)
...

emailca_params['CA'] = rootca
emailca = EmailSubCa.new(**emailca_params)
...

print rootca.Serial --> fine ;)
print emailca.Serial --> fine ;)

print emailca.Ca --> fine ;) (shows the CaCert instance)

however, the backreference doesn't work:
print rootca.SignedCaCerts
Traceback (most recent call last):
    File "certs.py", line 408, in ?
      print rootca.SignedCaCerts
    File "<string>", line 1, in <lambda>
    File "/usr/lib/python2.2/site-packages/SQLObject/Join.py", line 104,
in performJoin
      inst.id)
    File "/usr/lib/python2.2/site-packages/SQLObject/DBConnection.py",
line 309, in _SO_selectJoin
      return self.queryAll("SELECT %s FROM %s WHERE %s = %s" %
    File "/usr/lib/python2.2/site-packages/SQLObject/DBConnection.py",
line 139, in queryAll
      return self._runWithConnection(self._queryAll, s)
    File "/usr/lib/python2.2/site-packages/SQLObject/DBConnection.py",
line 74, in _runWithConnection
      val = meth(conn, *args)
    File "/usr/lib/python2.2/site-packages/SQLObject/DBConnection.py",
line 132, in _queryAll
      c.execute(s)
    File "/usr/lib/python2.2/site-packages/sqlite/main.py", line 243, in
execute
      self.rs = self.con.db.execute(SQL)
_sqlite.DatabaseError: no such column: ca_cert_id

I'd expect that SignedCaCerts = MultipleJoin('SubCaCert') will create a
"sub_ca_cert_id" column which in turn will be asked for and not
"ca_cert_id". Any ideas?

Thanks
   Paul

Re: [SQLObject] [newbie] problem with MultipleJoin

[<pa...@su...>]

paul k=F6lle wrote:

just for the record:

> class CaCert(CertItem):
>    SignedCaCerts =3D MultipleJoin('SubCaCert')
>    ...
>=20
> class SubCaCert(CertItem):
>    Ca =3D ForeignKey('CaCert')
>    ...
That's apparently wrong. In order to work such the name of the column=20
*has* to be the same as the referenced object (case insensitive?). While=20
  the documentation gives a perfectly valid example ( person =3D=20
ForeignKey('Person')) it was not clear to me that those strings have to=20
be equal. The documentation notes the correspondence of the 'Person'=20
string with another class in the db nothing more. Maybe it's just me=20
knowing almost nothing about db/sql/whatever ... ;)

  :P

Re: [SQLObject] [newbie] problem with MultipleJoin

[Ian B. <ia...@co...>]

paul kölle wrote:
> paul kölle wrote:
> 
> just for the record:
> 
>> class CaCert(CertItem):
>>    SignedCaCerts = MultipleJoin('SubCaCert')
>>    ...
>>
>> class SubCaCert(CertItem):
>>    Ca = ForeignKey('CaCert')
>>    ...
> 
> That's apparently wrong. In order to work such the name of the column 
> *has* to be the same as the referenced object (case insensitive?). While 
>  the documentation gives a perfectly valid example ( person = 
> ForeignKey('Person')) it was not clear to me that those strings have to 
> be equal. The documentation notes the correspondence of the 'Person' 
> string with another class in the db nothing more. Maybe it's just me 
> knowing almost nothing about db/sql/whatever ... ;)

You did encounter a bug.  There's already a bug reported that is, I 
think, related to this -- basically an issue with the automatic naming 
with MultipleJoins.  When I started using attributes instead of giving 
the names in the MultipleJoin constructor, I didn't convert everything 
over properly.

-- 
Ian Bicking  /  ia...@co...  / http://blog.ianbicking.org