Hello,
I am pretty determined to find a way to get (a simplified version of)
multiple inheritance working with SA. The simplification lies in that
no overriding of attributes will be possible (but I don't know whether
that is significant). I was thinking of a schema as follows:
--------------------------------------------------------------------------------------
metadata = MetaData()
base1_table = Table("base1_table", metadata,
Column('id', Integer, primary_key=True),
Column('str', String)
)
base2_table = Table("base2_table", metadata,
Column('id', Integer, primary_key=True),
Column('int', Integer)
)
claz1_table = Table("claz1_table", metadata,
Column('id', Integer, primary_key=True),
Column('base1_id', None, ForeignKey('base1_table.id')),
Column('base2_id', None, ForeignKey('base2_table.id')),
Column('assoc_id', None, ForeignKey('assoc_table.id'))
)
assoc_table = Table("assoc_table", metadata,
Column('id', Integer, primary_key=True),
Column('name', String(50), nullable=False),
Column('type', String(50), nullable=False)
)
base3_table = Table("base3_table", metadata,
Column('id', Integer, primary_key=True),
Column('assoc_id', None, ForeignKey('assoc_table.id')),
Column('bool', Boolean)
)
claz2_table = Table("claz2_table", metadata,
Column('id', Integer, primary_key=True),
Column('base3_id', None, ForeignKey('base3_table.id')),
Column('date', Date)
)
class base1(object):
pass
class base2(object):
pass
class base3(object):
pass
class claz1(base1, base2):
pass
class claz2(base3):
pass
# do mappings, relationships and e.g. be able to
c1 = claz1(str = "hello", int = 17)
setattr(c1, name, claz2(bool = True, date = Date(2010,9,10)))
-----------------------------------------------------------------------------------------------------------------
I am still pretty new to SA. Can anyone give me any hints, tips,
issues with this scheme (e.g. about how to do the mappings,
descriptors, etc)?
The step after will be to write factory functions/metaclasses to
generate these dynamically.
Multiple inheritance is very important for my use case.
Cheers, Lars
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