Question

I’m using SQLAlchemy in project that is not a web application. It is a server application that loads number of different objects from database and modifies them locally, but don’t want to save those updates to the database each time a commit is issued. I was previously working with Django ORM for some web projects and found it better suited for what I’m trying to achieve. In Django ORM I could .save() each object whenever I wanted without saving other things I may not want to save. I understand why it works like this in SQLAlchemy, but I wonder how I could do this in the Django-like way?

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Update:
To make it easier to understand what I’m trying to achieve, I’ll provide you an example.

This is how it works actually:

a = MyModel.query.get(1)
b = MyModel.query.get(1)

a.somefield = 1
b.somefield = 2

# this will save both of changed models
session.commit()

This is how I want it to work:

a = MyModel.query.get(1)
b = MyModel.query.get(1)

a.somefield = 1
b.somefield = 2

a.save()
# I didn't want to save b, changes of b weren't committed

I want to have greater control of what is actually saved. I want to save changes of each object every 5 minute or so.

Answer 1

I use something like:

class BaseModel(object):
    def save(self, commit=True):
        # this part can be optimized.
        try:
            db.session.add(self)
        except FlushError:
            # In case of an update operation.
            pass

        if commit:
            db.session.commit()

    def delete(self, commit=True):
        db.session.delete(self)

        if commit:
            db.session.commit()

and then I define my models as:

class User(db.Model, BaseModel)

So, now I can do:

u = User(username='foo', password='bar')
u.save()

This is what you were planning to achieve ?