pdo is a common interface layer for databases for php, like jdbc in java or ado.net in C# so I can use the same api for any supported database. In python technically dbapi standard exists for the same task, but the driver apis annoyingly vary so much between themselves that if i have to i go with sqlalchemy, but it's no longer a lightweight solution

That makes sense, thanks. It seems I somehow forgot that databases other than Postgres exist.