From: Tutor <[email protected]> on behalf of GMX
<[email protected]>
Sent: Monday, September 11, 2017 9:38 AM
To: [email protected]
Subject: [Tutor] How to create an object in database only if the object is not
already there?
<snip>
Now when I create a Course object like this:
>>> Course(title=‘A new course’)
An object is create in the database. I don’t want to have this behaviour, but
what I want to be doing is create a Course object
and then only commit in the database if the course is not already available in
the database.
===> I have no experience with Pony, but with Sqlalchemy one could do something
like:
if not session.query(Course.title).filter_by(title=‘A new course’).first():
course = Course(title=‘A new course’)
Or perhaps you could set a primary key constraint on course title.
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