modeling-users

[Modeling-users] SQLite, problemas with Floats

[Ernesto R. <er...@si...>]

Hi again (sorry for the attack),

I'm using Modeling 0.9-pre15 and sqlite 2.8.6

When I do a fetch for objects with float attributes, these are string =
and not float. Say:
....
>>> accounts=3Dec.fetch('Account')
>>> accounts[0].getAmount()
'0.0'

I know that sqlite stores everything as strings, but it should be =
converted to float in Python, and I don't know where to do this. The =
problem is (suppose account has a name):
>>> accounts[0].setName('sales')
>>> ec.saveChanges()
....
Modeling.Validation.ValidationException: Validation for key saldo =
failed:
- Wrong type
Validation for key OBJECT_WIDE_VALIDATION failed:
- Validation of object <Conta.Cuenta.Cuenta instance at 0x00DC4FE8> as a =
whole failed

because although it has been initialised with 0.0 now it is '0.0' (type =
string).

Thanx in advance,
Erny

Re: [Modeling-users] SQLite, problemas with Floats

[Ernesto R. <er...@si...>]

Ok, I've tracked down this and see the following issue:

In DatabaseContext.py, near line 1540, the following two lines appear:

   if value and attr.type() =3D=3D 'DateTime':
      value=3Dattr.convertStringToAttributeType(value)

So we only do type conversion if attr.type() =3D=3D 'DateTime' and value =
is not empty ???
Is this an optimization?

Shouldn't we force a conversion to Python types whenver possible? Should =
this work be done by the database layer (perhaps we need custom =
conversions depending on the database)?

Erny



----- Original Message -----=20
From: "Ernesto Revilla" <er...@si...>
To: "modeling-users" <mod...@li...>
Sent: Wednesday, September 17, 2003 1:31 AM
Subject: [Modeling-users] SQLite, problemas with Floats


Hi again (sorry for the attack),

I'm using Modeling 0.9-pre15 and sqlite 2.8.6

When I do a fetch for objects with float attributes, these are string =
and not float. Say:
....
>>> accounts=3Dec.fetch('Account')
>>> accounts[0].getAmount()
'0.0'

I know that sqlite stores everything as strings, but it should be =
converted to float in Python, and I don't know where to do this. The =
problem is (suppose account has a name):
>>> accounts[0].setName('sales')
>>> ec.saveChanges()
....
Modeling.Validation.ValidationException: Validation for key saldo =
failed:
- Wrong type
Validation for key OBJECT_WIDE_VALIDATION failed:
- Validation of object <Conta.Cuenta.Cuenta instance at 0x00DC4FE8> as a =
whole failed

because although it has been initialised with 0.0 now it is '0.0' (type =
string).

Thanx in advance,
Erny




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Re: [Modeling-users] SQLite, problemas with Floats

[Sebastien B. <sbi...@us...>]

"Ernesto Revilla" <er...@si...> wrote:
> Ok, I've tracked down this and see the following issue:
>=20
> In DatabaseContext.py, near line 1540, the following two lines appear:
>=20
>    if value and attr.type() =3D=3D 'DateTime':
>       value=3Dattr.convertStringToAttributeType(value)
>=20
> So we only do type conversion if attr.type() =3D=3D 'DateTime' and value =
is not empty ???
> Is this an optimization?
>=20
> Shouldn't we force a conversion to Python types whenver possible? Should =
this work be done by the database layer (perhaps we need custom conversions=
 depending on the database)?

Usually these type conversions are done by the python adaptors --but
right, everything in sqlite is string, but I can't remeber how pysqlite
handles this, and I can't test this here.
  I've got to check this, especially why this is not catched by the
unittests; I'll have a look at it this evening and will report with
further details then.

-- S=E9bastien.

> ----- Original Message -----=20
> From: "Ernesto Revilla" <er...@si...>
> To: "modeling-users" <mod...@li...>
> Sent: Wednesday, September 17, 2003 1:31 AM
> Subject: [Modeling-users] SQLite, problemas with Floats
>=20
>=20
> Hi again (sorry for the attack),
>=20
> I'm using Modeling 0.9-pre15 and sqlite 2.8.6
>=20
> When I do a fetch for objects with float attributes, these are string and=
 not float. Say:
> ....
> >>> accounts=3Dec.fetch('Account')
> >>> accounts[0].getAmount()
> '0.0'
>=20
> I know that sqlite stores everything as strings, but it should be convert=
ed to float in Python, and I don't know where to do this. The problem is (s=
uppose account has a name):
> >>> accounts[0].setName('sales')
> >>> ec.saveChanges()
> ....
> Modeling.Validation.ValidationException: Validation for key saldo failed:
> - Wrong type
> Validation for key OBJECT_WIDE_VALIDATION failed:
> - Validation of object <Conta.Cuenta.Cuenta instance at 0x00DC4FE8> as a =
whole failed
>=20
> because although it has been initialised with 0.0 now it is '0.0' (type s=
tring).
>=20
> Thanx in advance,
> Erny

Re: [Modeling-users] SQLite, problemas with Floats

[Sebastien B. <sbi...@us...>]

        Hi,

"Ernesto Revilla" <er...@si...> wrote:
> Hi again (sorry for the attack),
>=20
> I'm using Modeling 0.9-pre15 and sqlite 2.8.6
>=20
> When I do a fetch for objects with float attributes, these are string and=
 not float. Say:
> ....
> >>> accounts=3Dec.fetch('Account')
> >>> accounts[0].getAmount()
> '0.0'

Which version of pysqlite are you currently using? I just checked the
recommended version (cf. http://modeling.sf.net/installation.html)
i.e. pysqlite v0.4.3, and this version does cast the types as expected:

>>> import sqlite
>>> sqlite.version
'0.4.3'
>>> cnx=3Dsqlite.connect('db_AuthorBooks.db')
>>> cur=3Dcnx.cursor()
>>> cur.execute("SELECT t0.ID, t0.LAST_NAME, t0.FIRST_NAME, t0.AGE, t0.BIRT=
HDAY, t0.FK_WRITER_ID FROM WRITER t0 WHERE t0.id=3D1")
>>> cur.fetchall()
[(1, 'Cleese', 'John', 24, <DateTime object for '1939-10-27 08:31:15.00' at=
 81d7ea8>, None)]


I couldn't find any clue on when this was introduced, however. Could you
check your own version and report? Thanks.

-- S=E9bastien.