[Sqlalchemy-tickets] Issue #3541: Undesired SQL generated on update (zzzeek/sqlalchemy)

[Gorka E. <iss...@bi...>]

New issue 3541: Undesired SQL generated on update
https://bitbucket.org/zzzeek/sqlalchemy/issues/3541/undesired-sql-generated-on-update

Gorka Eguileor:

In some SQL DBs the UPDATE operation is order dependent, so the operation behaves differently depending on the order of the values.
 
As an example, a volumes table with columns 'status' and 'previous_status' and we want to update a volume that has 'available' in the status column.
 
If the SQL query is generated as:

    UPDATE volumes SET previous_status=status, status='new' WHERE id=1;
 
This will result in a volume with 'new' status and 'available' previous_status both on SQLite and MariaDB, but if columns get reversed and the query is generated as:

    UPDATE volumes SET status='new', previous_status=status WHERE id=1;
 
We will get the same result in SQLite but will result in a volume with status and previous_status set to 'new' in MariaDB, which is not what we want.

And this cannot be selected when calling update or values on update().