Hello,
the example code for multiple table inheritance
(http://www.sqlalchemy.org/docs/adv_datamapping.myt#advdatamapping_inheritance_multiple)
does not work with the previously introduce class setup
(http://www.sqlalchemy.org/docs/adv_datamapping.myt#advdatamapping_inheritance)
The attached patch solves this.
Cheers, Sol.
Index: doc/build/content/adv_datamapping.txt
===================================================================
--- doc/build/content/adv_datamapping.txt (revision 1722)
+++ doc/build/content/adv_datamapping.txt (working copy)
@@ -457,22 +457,22 @@
Like concrete table inheritance, this can be done non-polymorphically, or with a little more complexity, polymorphically:
{python title="Multiple Table Inheritance, Non-polymorphic"}
- people = Table('people', metadata,
+ employees = Table('employees', metadata,
Column('person_id', Integer, primary_key=True),
Column('name', String(50)),
Column('type', String(30)))
engineers = Table('engineers', metadata,
- Column('person_id', Integer, ForeignKey('people.person_id'), primary_key=True),
+ Column('person_id', Integer, ForeignKey('employees.person_id'), primary_key=True),
Column('engineer_info', String(50)),
)
managers = Table('managers', metadata,
- Column('person_id', Integer, ForeignKey('people.person_id'), primary_key=True),
+ Column('person_id', Integer, ForeignKey('employees.person_id'), primary_key=True),
Column('manager_data', String(50)),
)
- person_mapper = mapper(Person, people)
+ person_mapper = mapper(Employee, employees)
mapper(Engineer, engineers, inherits=person_mapper)
mapper(Manager, managers, inherits=person_mapper)
@@ -481,15 +481,16 @@
{python title="Multiple Table Inheritance, Polymorphic"}
person_join = polymorphic_union(
{
- 'engineer':people.join(engineers),
- 'manager':people.join(managers),
- 'person':people.select(people.c.type=='person'),
+ 'engineer':employees.join(engineers),
+ 'manager':employees.join(managers),
+ 'person':employees.select(employees.c.type=='person'),
}, None, 'pjoin')
- person_mapper = mapper(Person, people, select_table=person_join, polymorphic_on=person_join.c.type, polymorphic_identity='person')
+ person_mapper = mapper(Employee, employees, select_table=person_join, polymorphic_on=person_join.c.type, polymorphic_identity='person')
mapper(Engineer, engineers, inherits=person_mapper, polymorphic_identity='engineer')
mapper(Manager, managers, inherits=person_mapper, polymorphic_identity='manager')
+
The join condition in a multiple table inheritance relationship can be specified explicitly, using `inherit_condition`:
{python}
-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys -- and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Sqlalchemy-users mailing list
Sqlalchemy-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/sqlalchemy-users
