CODEWITHSUNDEEP
mysqlpython-3.xflask-sqlalchemyflask-restful
Natarich J
Natarich J

Reputation: 425

Flask Sqlalchemy how to not auto-update TIMSTAMP column when update a row

I have a model:

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String, nullable=False)
    password = db.Column(db.String, nullable=False)
    created_time = db.Column(db.TIMESTAMP, nullable=False)

However, every time I updated name or password, the timestamp created_time would be updated, but I don't want created_time to be updated. 

# the way I update a user's info
class UserController(Resource):
    def get(self):
        user = User.query.filter_by(id=1).first()  # a user had been created before
        user.name = "new_name"
        db.session.commit()  
       # as of here, not only `name` but also `created_time` will be update

How to stop created_time from auto-updating when updating a row?

Edit 1

To be more precise, I would like to know about the mechanism of db.TIMESTAMP, and more specifically, to resolve the issue that when I update other columns in a row db.TIMESTAMP column is also updated.

I would instead want the value in db.TIMESTAMP column to be fixed at the time the row is created, and that value should never change regardless of how values in other columns change.

P.S. To avoid misunderstanding, I know TIMESTAMP may not be the most appropriate type for created_time column, but the above code is only for illustrating purposes.

Upvotes: 2

Views: 2463

Answers (2)

ahmed
ahmed

Reputation: 51

Well, from what I understand, the on_update event trigger which causes your problem is not the default, and it should not be generated without being told explicitly.

see more: Marking Implicitly Generated Values, timestamps, and Triggered Columns

The Ideal way to create created/modified timestamps is like this

class Base():
    id = db.Column(db.Integer, primary_key=True)
    created_time = db.Column(db.DateTime, server_default=db.func.now())
    modified_time = db.Column(db.DateTime, server_default=db.func.now(), onupdate=db.func.now())

src: Define Output Column In Flask-Sqlalchemy

here I found good references which may help you solve the problem. How to stop SQLAlchemy from adding an ON UPDATE clause to a TIMESTAMP column by default

Upvotes: 2

Alec Gerona
Alec Gerona

Reputation: 2897

Your column for your created_time should be db.DateTime.

Upvotes: 1

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