Combination of (pg) on_conflict_do_update and ORM's bulk_insert_mappings

[Anthony Catel]

Hey,

I'm looking for a way to builk upsert using pg's "on_conflict_do_update"  in a way that would allow me to use a mapper classe (because the objects I want to insert/update are joined-inheritance).

bulk_insert_mappings() would allow me to use its "return_defaults" and to provide a Mapper classe. But I couldn't figure out a way to combine it with "on_conflict_do_update".

Any hack I could use to glue these two?

Thanks!

[Mike Bayer]

you can use a mapped class directly with pg's insert() construct:

insert(MyClass).values(...).on_conflict(...)

are you referring to being able to pass instances of mapped objects to the values?   Just pull these out of each object's `__dict__`, it's much more efficient than bulk_insert_mappings.    You can get object instances back too using the technique shown at https://docs.sqlalchemy.org/en/14/orm/session_basics.html#selecting-orm-objects-inline-with-update-returning-or-insert-returning , basically create the SQL insert() statement you want, make sure it uses returning(), then use select(MyModel).from_statement(my_insert) to get object instances back.

--

SQLAlchemy -

The Python SQL Toolkit and Object Relational Mapper

 

http://www.sqlalchemy.org/

 

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description.

---

You received this message because you are subscribed to the Google Groups "sqlalchemy" group.

To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/48c6462a-c4fd-46c7-aead-464b29a03e27n%40googlegroups.com.

[Mike Bayer]

let me try to make an example

To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/1dda86f7-1a70-4ba8-8b0d-fb45c3d62bc5%40www.fastmail.com.

[Mike Bayer]

not exactly what you asked for but this seems pretty easy to use:

https://docs.sqlalchemy.org/en/14/orm/persistence_techniques.html#using-postgresql-on-conflict-with-returning-to-return-upserted-orm-objects

To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/ba6e9820-cb52-4a2a-b405-3b85833327ca%40www.fastmail.com.

[Anthony Catel]

Hey Mike,

Thanks for the quick reply!
I already tried to pass a mapped class to Insert() but it didn't work (because the mapper is joined-inheritance and so it needs to insert a row in both the Base parent table and the child table). Got an error about "Unconsumed column names", because the values contains (through inheritance) fields from both table.

I ended up doing a "mass" query check to separate bulk_insert_mappings and bulk_update_mappings :

 https://pastebin.com/raw/JTpSsMEw

Not the best performance deal compared to on_conflict() I guess but that's all I found for now.