Re: Adaptation in psycopg3

On Wed, 25 Nov 2020 at 18:00, listas <listas@soft-com.es> wrote:

> Thank for your replies, I will use "=any(params list)" in psycopg3

No problem. But if it was not clear, this is something that works
already in psycopg2 too: it could be useful if you want to port code
later.


> The second question is: if psycopg3 is going to do the automatic cast of
> the types, will it be able to distinguish between a json and a list of
> values?.
> Example:
>
> data = ["a", "b", "c"]
> idList = [4,7,2]
>
> cursor.execute("update mytable set jsfield=%s where id = any(%s)",
> (data, idList))
>
> What will be the correct syntax in this case?

You would do like in psycopg2. There isn't a single json type in
python (it could be a list, dict, number, None...) so there is a
"Json" wrapper to tell psycopg to pass e.g. a json number rather than
a number-number:
https://www.psycopg.org/docs/extras.html?highlight=json#json-adaptation

What you would do, both in psycopg2 and 3, would be something like:

    cursor.execute("update mytable set jsfield=%s where id = any(%s)",
    (Json(data), idList))

Code like this should work in both versions.

Cheers

-- Daniele