Message-ID: <gh-postgresql-interfaces-psqlodbc-117@github.com>
From: "omeuid (@omeuid)" <noreply+omeuid@github.com>
To: "postgresql-interfaces/psqlodbc" <noreply+postgresql-interfaces-psqlodbc@github.com>
Date: Wed, 21 May 2025 14:56:44 +0000
Subject: [postgresql-interfaces/psqlodbc] issue #117: How to use PostgreSQL extended protocol with ODBC driver executing a parameterized sentence.
List-Id: <gh-postgresql-interfaces-psqlodbc.github.com>
X-GitHub-Author-Id: 6940566
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X-GitHub-Issue: 117
X-GitHub-Repo: postgresql-interfaces/psqlodbc
X-GitHub-State: open
X-GitHub-Type: issue
X-GitHub-Url: https://github.com/postgresql-interfaces/psqlodbc/issues/117
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Hi,

Is there a way to configure the ODBC driver to use the extended protocol when running a parameterized query?

Let's assume the following Python client.

> import pyodbc
> 
> def connect_to_odbc(uri):
>     conn = pyodbc.connect(uri)
>     return conn
> 
> def execute_query(conn, query):
>     cursor = conn.cursor()
>     cursor.execute(query, 1)
>     result = cursor.fetchall()
>     return result
>    
> uri = 'DSN=MyDSN'
> 
> conn = connect_to_odbc(uri)
> query = 'SELECT * from mytable where id = ?'
> 
> result = execute_query(conn, query)
> 
> for row in result:
>     print(row)
> 
> conn.close()

If the DSN is configured with 'server side prepare' option set to 1 (and also batch size is set to 1):

* I expected that the driver would send P/B/E messages.
* However, what I'm observing is that the driver only sends a Q message, with the parameter already replaced.

Could you confirm if this is the expected behaviour? 

Is there anything that I can configure in the driver in order to get the behaviour that I was expecting?

Regards