allen.fowler wrote:
>
>> ...> To clarify:
>>
>>
>>> I am using SQLAlchemy's Declarative Base to fully define and create my
>>> database.
>>>
>>> For instance, there is a simple class/table Records, and I would like
>>> to define a class CurrentRecords that is implemented in the database
>>> as a view on Records.
>>>
>>> In this way, I can avoid polluting my application code with filtering
>>> out all the non-active records every time I want to query Records.
>>>
>> Just define CurrentRecords as a table, i.e. in my app one of my views is:
>>
>> class Vconsumption(Base):
>> __table__ = sa.Table(u'vconsumption', metadata,
>> sa.Column(u'consumptionid', sa.Integer(),
>> sa.ForeignKey(u'consumption.consumptionid'), primary_key=True),
>> ...
>> )
>>
>> consumption = sao.relation(Consumption)
>>
>> And I relate it back to the real consumption table, but never
>> write/flush the view and do have to have a unique key which you define
>> as "primary key" to SA.
>>
>> Werner
>>
>
> What functional gain does this approuch provide over just querying the
> Consumption table? I am not clear on how you are using this.... can
> you clarify?
>
As you can see from the view definition (below) it just contains id's
from four tables plus a description which comes from one of two tables,
but in the application I sometimes need more details from the actual
consumption details, therefore the relation.
> As an aside, I wonder if it is possible to just subclass my Records
> object so that the CurrentRecords class adds/enforces certain
> filter_by parameters for any query against it.
>
Do not know the answer to this, nor do I have a guess :-) .
Werner
Partial view definition:
CREATE VIEW VCONSUMPTION(
CONSUMPTIONID,
FK_CBBOTTLEID,
DESCRIPTION,
FK_CONSEVENTID,
FK_CONSBATCHID)
AS
select con.consumptionid,
con.fk_cbbottleid,
coalesce(cb.description, ce.description),
ce.conseventid,
cb.consbatchid
etc
> Thank you. :)
>
>
>
> >
>
>
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