Python sqlalchemy.orm 模块，relation() 实例源码

def orm_load_flucstrucs(man):
    man.flucstruc_table = Table('flucstrucs', man.metadata,
                            Column('basedata_id', Integer, ForeignKey('basedata.basedata_id'), primary_key=True),
                            Column('_binary_svs', Integer),
                            Column('freq', Float),
                            Column('a12', Float),
                            Column('t0', Float),    
                            Column('p', Float),    
                            Column('H', Float),    
                            Column('dphase_id', Integer, ForeignKey('baseordereddataset.id'), nullable=False))    
    man.metadata.create_all()
    mapper(FlucStruc, man.flucstruc_table, inherits=BaseData,
           polymorphic_identity='flucstruc', properties={'dphase': relation(BaseOrderedDataSet)})

def orm_load_channel(man):
    man.channel_table = Table('channel', man.metadata,
                            Column('id', Integer, primary_key=True),
                            Column('name', String(200), nullable=False),
                            Column('coords_id', Integer, ForeignKey('coords.id'), nullable=False))
    #man.metadata.create_all()
    mapper(Channel, man.channel_table, properties={'coords': relation(Coords)})

def orm_load_channellist(man):
    man.channellist_table = Table('channellist', man.metadata,
                                  Column('id', Integer, primary_key=True))

    #man.metadata.create_all()
    mapper(ChannelList, man.channellist_table,
           properties={'_channels': relation(Channel, secondary=man.channel_association_table)})

def orm_load_dataset(man):
    man.dataset_table = Table('dataset', man.metadata,
                            Column('basedataset_id', Integer, ForeignKey('basedataset.id'), primary_key=True))
    #man.metadata.create_all()
    mapper(DataSet, man.dataset_table, inherits=BaseDataSet, polymorphic_identity='dataset',
           properties={'data': relation(BaseData, secondary=man.data_basedataset_table, backref='datasets', cascade='all', collection_class=set)})

def orm_load_baseordereddataset(man):
    man.baseordereddataset_table = Table('baseordereddataset', man.metadata,
                                         Column('id', Integer, primary_key=True),
                                         Column('created', DateTime),
                                         Column('label', String(50), nullable=False, unique=True),
                                         Column('type', String(30), nullable=False))

    man.ordereditems_table = Table('ordereddata_items', man.metadata,
                         Column('dataset_id', Integer, ForeignKey('baseordereddataset.id'),
                                primary_key=True),
                         Column('item_id', Integer, ForeignKey('basedata.basedata_id'),
                                primary_key=True),
                         Column('index', Integer, nullable=False)
                         )

    man.metadata.create_all()

    mapper(BaseOrderedDataSet, man.baseordereddataset_table,
           polymorphic_on=man.baseordereddataset_table.c.type, polymorphic_identity='base_ordered_dataset',
           properties={'data_items': relation(OrderedDataSetItem,
                                                  backref='ordered_datasets_items',
                                                  cascade='all, delete-orphan',
                                                  collection_class=column_mapped_collection(man.ordereditems_table.c.index))
                       }
           )
    mapper(OrderedDataSetItem, man.ordereditems_table, properties={
        'item': relation(BaseData, lazy='joined', backref='dataitem')
        })