On Sep 28, 2010, at 4:01 PM, Michael Bayer wrote:
>
> On Sep 28, 2010, at 3:28 PM, Mark Erbaugh wrote:
>
>> I have a self-referential table:
>>
>> class L3Acct(BASE):
>>
>> __tablename__ = 'l3_acct'
>>
>> id = Column(Integer, primary_key=True)
>> parent = Column(ForeignKey('l3_acct.id'))
>>
>> [....]
>>
>>
>> When adding new rows to the table, the id field is not assigned a value
>> until the data is actually written to the database. When adding several
>> rows to a session object is there a way for a new row to reference a row
>> that has previously been added in the same batch, but hasn't been assigned
>> an id yet?
>
> sure, you use the relation() function at the class level to associate L3Acct
> instances with their parent instance, and establish the linkage at the object
> level, rather than the pk/fk level.
>
> This would be many-to-one, make sure you follow whats at
> http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
> carefully (including the remote_side flag). Those are the 0.6 docs but
> configuration for 0.5.8 is the same (except relationship() is relation()).
>
Michael,
Thanks. I've already used a relation to add child records to a separate table,
I hadn't thought of doing that with the same table. I'm still trying to get my
head out of directly working with SQL and working with the ORM.
Mark
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