you would need to accomplish this manually.
existing_obj = session.query(MyClass).get(obj.id)
if existing_obj is not None:
existing_obj.links.extend(obj.links)
obj = session.merge(obj)
On Sat, Sep 12, 2020, at 3:45 AM, sonsshh wrote:
> Hi,
>
> I'm trying to change the behavior of Postgres ARRAY type when calling
>
> *session.merge(obj)*
>
> where *obj* has a *links *ARRAY(Text) column.
>
> What I want is as below:
> *obj = Obj(links=['link2'],...)*
> * in DB I have obj row already and obj.links=['link1']*
> * session.merge(obj)*
> * session.commit() updates obj.links=['link1', 'link2'] instead of
> overwriting obj.links=['link2']*
>
> I want this sql to be emitted when updating this field.
>
> * CASE WHEN obj.links IS NULL *
> * OR NOT ARRAY[**obj.links**] @> %(links)s
> THEN array_cat(**obj.links**, %(links)s)
> ELSE **obj.links** END*
>
> I've been researching but still got no clue where to start.
> Is there anyone who can help?
>
> Thanks a lot,
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
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SQLAlchemy -
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http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
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