What is the `connection` parameter of MapperExtension in sqlalchemy?
-
01-10-2019 - |
Question
The class MapperExtension
has some methods, and before_insert
, before_update
, ... all have a parameter connection
.
def before_insert(self, mapper, connection, instance):
I've read the documents of MapperExtension
, but found nothing about this connection
. What is it? And how to use it?
Solution
It's an instance of Connection
class. Recent versions of SQLAlchemy distribution have examples directory, see examples/nested_sets/nested_sets.py to get an idea on how to use it in mapper extension.
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