Hi,
I am using alembic to apply a migration for a postgresql view using an *async
*engine.
I can see this successfully applied in the database.
I have the following declarative mapped class to the view, defined as:
*class MailingListView(Base): """View for mailing labels. After
metata reflection from db -> model expecting columns to be available on
this class. """*
* __tablename__ = "mailing_list_view"*
* # Specify the column override from the underlying view that is the
primary key id = Column(UUID(as_uuid=True), primary_key=True) *
* # Expecting these columns below to be mapped in this class after
# metadata reflection. Currently have to uncomment these # to manually
synchronise with view! # # addressee = Column(String) # street =
Column(String) # town = Column(String) # county = Column(String) #
postcode = Column(String) # cursor = Column(String)*
I am reflecting the views using the following:
* def use_inspector(conn): inspector = inspect(conn)
return inspector.get_view_names() views = await
connection.run_sync(use_inspector) # I can see the table columns in
__table__.c.keys() # after the reflection below has run*
* await connection.run_sync(*
* target_metadata.reflect,*
* only=views,*
* views=True,*
* extend_existing=True,*
* )*
After performing the above reflection I can see that my mapped model has
the underlyingtable columns updated with those defined in the underlying
view.
*obj = MailingListView()obj.__table__.c.keys()*
However, the properties of my mapped class are not updated after
reflection, raising an exception:
*obj = MailingListView()obj.town = "town" # this raises an exception with
unavailable property*
How is it possible for a postgresql db (asyncpg) + async sqlalchemy to:
Synchronise the columns of a declarative model with its underlying table
after metadata reflection. Currently, I have to manually specify the
columns in the declarative model.
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
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