For simple fields, we can use Column.info for attaching FA-related metdata to columns. For ManyToOne fields, we can change info for related ForeignKey column. But for ManyToMany fields, there is not a simple way.
Suppose this schema: (simple ManyToMany relation)
class Item(Base):
__tablename__ = 'items'
id = Column(Integer, primary_key=True)
name = Column(Unicode(255))
model_items_table = Table('model_items', Base.metadata,
Column('item_id', Integer, ForeignKey(Item.id), primary_key=True),
Column('model_id', Integer, ForeignKey('models.id'), primary_key=True))
class MyModel(Base):
__tablename__ = 'models'
id = Column(Integer, primary_key=True)
name = Column(Unicode(255))
many_to_many = relationship(Item, secondary=model_items_table)
We want to change ManyToMany renderer by adding info={'renderer: ...} keyword argument for a Column, but which Column?
The right Column should be one of columns in intermediate table(model_items), but adding this doesn't work for either of those two columns.
Default implementation of AttributeField.info() only checks info attribute of Item.id which is not sufficient.
For simple fields, we can use
Column.infofor attaching FA-related metdata to columns. For ManyToOne fields, we can changeinfofor related ForeignKey column. But for ManyToMany fields, there is not a simple way.Suppose this schema: (simple ManyToMany relation)
We want to change ManyToMany renderer by adding
info={'renderer: ...}keyword argument for aColumn, but which Column?The right Column should be one of columns in intermediate table(
model_items), but adding this doesn't work for either of those two columns.Default implementation of
AttributeField.info()only checksinfoattribute ofItem.idwhich is not sufficient.