which join are u mentioning? and which result u want to save?
the query itself or the objects it returns after execution?
q = query(Line).join( Fiber, ...condition ).filter(....)
if ... return q.filter( 123...)
else: return q.filter( 456...)
building that q is not expensive;
saving it is fine but beware when sessions close/open etc.
svilen
On Tuesday 20 January 2009 16:33:16 Boudewijn Ector wrote:
> On Tue, Jan 20, 2009 at 8:24 AM, <a...@svilendobrev.com> wrote:
> > mmh, cant really grasp what u want to do.
> > what are Line.* attributes?
> >
> > .filter does and(), so this can be simplified:
> > q = query(Line).filter( models.Line.LineDiscarded ==
> > LineDiscarded ) if ...:
> > return q.filter( sites...)
> > else:
> > return q.filter( sites...)
>
> That will probably work fine, but I'd like to join Fiber and Line
> together, and save the result of the join itself.
> The definition of Line:
>
> fiberdb=# \d "Line";
> Table "public.Line"
> Column | Type
>
> | Modifiers
>
> ----------------------------+-----------------------------+--------
>------------------------------------------------- LineName
> | character varying(50) | not null ProviderName
> | character varying(50) | Length
> | integer | not null default
> nextval('"Line_Length_seq"'::regclass)
> Type | character varying(50) |
> MeasurementReport | text |
> Comment | text |
> LineDiscarded | character(1) |
> LineNamesReplacingThisLine | text |
> EndOfContractDate | timestamp without time zone |
> LineNameSURFnet | character varying(50) |
> SiteLocationCodeA | character varying(50) |
> SiteLocationCodeB | character varying(50) |
> last_updated | timestamp with time zone |
> last_updated_by | character varying(50) |
> GeoObjectID | integer |
> importedFromWKT | character(1) |
> ThirdPartyName | character varying(50) |
> GeoData | geometry |
> Indexes:
> "PRI_Line" PRIMARY KEY, btree ("LineName")
> "FKI_Line_GeoObject" btree ("GeoObjectID")
> "FKI_Line_Provider" btree ("ProviderName")
> "FKI_Line_Site" btree ("SiteLocationCodeA")
> "FKI_Line_SiteA" btree ("SiteLocationCodeA")
> "FKI_Line_SiteB" btree ("SiteLocationCodeB")
> Check constraints:
> "enforce_dims_Data" CHECK (ndims("GeoData") = 3)
> "enforce_srid_Data" CHECK (srid("GeoData") = 4326)
> Foreign-key constraints:
> "FK_Line_GeoObject" FOREIGN KEY ("GeoObjectID") REFERENCES
> "GeoObject"("GeoObjectID") ON UPDATE CASCADE ON DELETE CASCADE
> "FK_Line_Provider" FOREIGN KEY ("ProviderName") REFERENCES
> "Provider"("ProviderName") ON UPDATE CASCADE ON DELETE RESTRICT
> "FK_Line_SiteA" FOREIGN KEY ("SiteLocationCodeA") REFERENCES
> "Site"("SiteLocationCode") ON UPDATE CASCADE ON DELETE RESTRICT
> "FK_Line_SiteB" FOREIGN KEY ("SiteLocationCodeB") REFERENCES
> "Site"("SiteLocationCode") ON UPDATE CASCADE ON DELETE RESTRICT
>
>
>
> So, I get the SiteLocationCodeA and SiteLocationCodeB. I need to
> retrieve all fibers between them (because I'd like to have a look
> at the FiberInUse property between two SiteLocationCodes).
> So I join Fiber and Line using the LineName as key.
> Now, I should be able to have a look which Lines between A and B
> have Fibers which are not in use.
>
> But, more interesting things and filters might come in handy, in my
> search function. So I'd prefer to save the result of the join into
> a variable, so I don't need to do the join in every case of my
> search function.
>
>
> That's why.
>
> Cheers,
>
> Boudewijn Ector
>
>
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