I am working on my localization stuff and run into a problem when I want
to add an relationship to a class.
I based my code on
http://www.sqlalchemy.org/trac/wiki/UsageRecipes/Views , but maybe I
messed something up.
The following works:
r1 = session.query(db.Region_LV).get(175)
print type(result.country_lv)
print r1
print r1.country_lv.name
with this output:
Region_LV(centralkey=175, country_lv=Country_LV(centralkey=83,
created_at=datetime.datetime(2011, 9, 7, 9, 39, 10, 702000),
created_by=None, dialcode=30, fk_language_id=2, id=83, is2code=u'GR',
iswinecountry=1, name=u'Gr\xe8ce', shortname=None, un3code=u'GRC',
updated_at=datetime.datetime(2011, 9, 7, 9, 39, 10, 702000),
updated_by=None, website1=None, website2=None),
created_at=datetime.datetime(2011, 9, 7, 9, 39, 11, 452000),
created_by=None, fk_country_id=83, fk_language_id=2, id=175,
name=u'Sud-Ouest', shortname=u'Sud-Ouest',
updated_at=datetime.datetime(2011, 9, 7, 9, 39, 11, 452000),
updated_by=None)
Grèce
The model for all this is:
class Region(DeclarativeBase, mix.StandardColumnMixin):
__tablename__ = u'region'
centralkey = sa.Column(sa.BigInteger())
name = sa.Column(sa.Unicode(length=50), nullable=False)
shortname = sa.Column(sa.Unicode(length=10))
fk_country_id = sautils.reference_col('country')
__localize_columns__ = ['name', 'shortname']
Region_L, Region_LV = sautils.CreateLocalized(Region())
Region_LV.country_lv = sao.relationship('Country_LV')
CreateLocalized creates the "Region_LV" based on the usage recipe.
Now if I add:
Region_LV.language = sao.relationship('Language')
I get:
sqlalchemy.exc.ArgumentError: Could not determine join condition between
parent/child tables on relationship Region_LV.language. Specify a
'primaryjoin' expression. If 'secondary' is present, 'secondaryjoin' is
needed as well.
or:
Region_LV.language = sao.relationship('Language',
primaryjoin="Region_LV.fk_language_id==Language.id")
I get:
sqlalchemy.exc.ArgumentError: Could not determine relationship direction
for primaryjoin condition 'country_lv.fk_language_id = language.id', on
relationship Region_LV.language. Ensure that the referencing Column
objects have a ForeignKey present, or are otherwise part of a
ForeignKeyConstraint on their parent Table, or specify the foreign_keys
parameter to this relationship.
or:
Region_LV.language = sao.relationship('Language',
primaryjoin="Country_LV.fk_language_id==Language.id",
foreign_keys=[Country_LV.__table__.c.fk_language_id])
I get:
sqlalchemy.exc.ArgumentError: Column-based expression object expected
for argument 'foreign_keys'; got: 'Country_LV.fk_language_id', type
<type 'str'>
sqlalchemy.exc.ArgumentError: Could not locate any foreign-key-equated,
locally mapped column pairs for primaryjoin condition
'country_lv.fk_language_id = language.id' on relationship
Region_LV.language. For more relaxed rules on join conditions, the
relationship may be marked as viewonly=True.
Tried with "viewonly" but couldn't make that work either.
I guess/think my problem is that I don't define a ForeignKeyConstraint
for the "fk_language_id" column but I haven't found how this is done as
the Country_LV view is created using "from sqlalchemy.sql import table".
I'd appreciate any tips on how to get this to work.
Werner
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