I'm not sure how to do a join against a related record:
g=SiteEnergy.objects.filter(siteyear=9, energy__isofsite=False)
raise TypeError, "Cannot resolve keyword '%s' into field" % name
TypeError: Cannot resolve keyword 'energy' into field
g=SiteEnergy.objects.filter(siteyear=9, typer.isoffsite=False)
SyntaxError: keyword can't be an expression
The query looks like this is standard SQL (Postgres) -- I'm not sure of the
Django approach here.
SELECT
se.*
FROM
bm_siteenergy se, data_energy e
WHERE
se.typer_id = e.id
AND
e.isoffsite=FALSE;
Thanks for any help;
Rory
class SiteEnergy (models.Model):
'''
An Energy supply definition for a particular Site for a particular
Year of Assessment
'''
siteyear = models.ForeignKey (SiteYear)
typer = models.ForeignKey (Energy)
source = models.CharField ('Source' , maxlength =250)
usage = models.FloatField ('Usage' , max_digits=10 ,
decimal_places=2, default=0)
# units come from Energy
kwh = models.FloatField ('kWh' , max_digits=10 ,
decimal_places=2, default=0)
cwf = models.FloatField ('Carbon Factor', max_digits=13 ,
decimal_places=5, default=0)
from data/models.py:
class Energy (models.Model, General):
name = models.CharField ('EPLabel Energy Name', blank=False
,maxlength = 200)
localname = models.CharField ('Local Energy Name' , blank=True
,maxlength = 200)
factorname = models.CharField ('Factor Name' , blank=False
,maxlength = 50)
localfactorname = models.CharField('Local Factor Name' , blank=True
,maxlength = 50)
# factor numbers in format 999999.9999999 (9 hundred thousand to 7
decimal places)
unit = models.CharField ('Factor Unit' , blank=False
,maxlength = 50)
factor = models.FloatField ('Factor' , blank=False
,max_digits= 13 , decimal_places=7)
isreverse = models.BooleanField ('Reverse Factor' , blank=False
,default = False)
isoffsite = models.BooleanField ('Off Site' , blank=False
,default = False)
isthermal = models.BooleanField ('Thermal Type' , blank=False
,default = False)
created = models.DateTimeField (auto_now=True)
country = models.ForeignKey (Country)
Postgres tables:
eplabel=> \d bm_siteenergy
Table "public.bm_siteenergy"
Column | Type | Modifiers
-------------+------------------------+------------------------------------------------------------
id | integer | not null default
nextval('bm_siteenergy_id_seq'::regclass)
siteyear_id | integer | not null
typer_id | integer | not null
source | character varying(250) | not null
usage | numeric(10,2) | not null
kwh | numeric(10,2) | not null
cwf | numeric(13,5) | not null
Indexes:
"bm_siteenergy_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
"bm_siteenergy_siteyear_id_fkey" FOREIGN KEY (siteyear_id) REFERENCES
bm_siteyear(id)
"bm_siteenergy_typer_id_fkey" FOREIGN KEY (typer_id) REFERENCES
data_energy(id)
eplabel=> \d data_energy
Table "public.data_energy"
Column | Type |
Modifiers
-----------------+--------------------------+----------------------------------------------------------
id | integer | not null default
nextval('data_energy_id_seq'::regclass)
name | character varying(200) | not null
localname | character varying(200) | not null
factorname | character varying(50) | not null
localfactorname | character varying(50) | not null
unit | character varying(50) | not null
factor | numeric(13,7) | not null
isreverse | boolean | not null
isoffsite | boolean | not null
isthermal | boolean | not null
created | timestamp with time zone | not null
country_id | integer | not null
Indexes:
"data_energy_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
"data_energy_country_id_fkey" FOREIGN KEY (country_id) REFERENCES
data_country(id)
--
Rory Campbell-Lange
<[EMAIL PROTECTED]>
<www.campbell-lange.net>
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