The TypeDecorator is not used for defaults. You set "default=utc_timestamp()"
on your Column. The SQL expression is rendered directly in the INSERT when
no value given, no bind params used.
On Feb 8, 2011, at 10:13 PM, chris e wrote:
> I now have the code below, but the _oracle_utc_timestamp function is
> never called, even when I do explicitly set a value.
>
> class UTCTimestamp(TypeDecorator):
> impl = TIMESTAMP
>
> # add the UTC time zone info to naive timestamps
> def process_result_value(self, value, dialect) :
> if value != None :
> value = UTC.localize(value)
>
> return value
>
> def process_bind_param(self, value, dialect):
> # if we have a value convert it to UTC if needed
> if value != None :
> if value.tzinfo :
> value = value.astimezone(UTC)
> return value
>
> class utc_timestamp(FunctionElement):
> type = DateTime()
>
> @compiles(utc_timestamp)
> def _oracle_utc_timestamp(element, compiler, **kw):
> import pdb
> pdb.set_trace()
>
>
>
>
>
>
> On Feb 8, 6:09 pm, Michael Bayer <mike...@zzzcomputing.com> wrote:
>> On Feb 8, 2011, at 4:56 PM, chris e wrote:
>>
>>> To simplify date handling in a project on which I am working, I am
>>> storing UTC dates in the database in a timestamp with timezone field,
>>> however, because cx_Oracle does not have any timezone functionality, I
>>> need to cast the UTC timestamp I'm inserting into the database as a
>>> timestamp in UTC so that the database does not convert it to the db
>>> timezone. This also needs to apply to default values.
>>
>>> I have the following, however, it is not called for default values:
>>
>> The @compiles for _BindParamClause was never expected and is not covered
>> within a visit_insert() right now. Ticket #2042 is added. However, you're
>> better off using SQL level UTC functions for defaults in any case which
>> would be the workaround here. Here's one I use for PG + SQL Server. You
>> can add another for Oracle that includes your CAST expression if needed:
>>
>> class utcnow(expression.FunctionElement):
>> type = DateTime()
>>
>> @compiles(utcnow, 'postgresql')
>> def _pg_utcnow(element, compiler, **kw):
>> return "TIMEZONE('utc', CURRENT_TIMESTAMP)"
>>
>> @compiles(utcnow, 'mssql')
>> def _ms_utcnow(element, compiler, **kw):
>> return "GETUTCDATE()"
>>
>>> from pytz import UTC
>>> class UTCDateTime(TypeDecorator):
>>> impl = TIMESTAMP
>>
>>> # add the UTC time zone info to naive timestamps
>>> def process_result_value(self, value, dialect) :
>>> if value != None :
>>> value = UTC.localize(value)
>>
>>> return value
>>
>>> @compiles(_BindParamClause)
>>> def _compile_utc_date(element, compiler, **kw):
>>> if isinstance(element.type, UTCDateTime) :
>>> return "from_tz(cast(%s as timestamp), 'UTC')" \
>>> % compiler.visit_bindparam(element, **kw)
>>
>>> return compiler.visit_bindparam(element, **kw)
>>
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