CODEWITHSUNDEEP
pythonflasksqlalchemyflask-sqlalchemy
Robbie Milejczak
Robbie Milejczak

Reputation: 5780

Flask, prevent SQLAlchemy from adding values that are not specified when instantiating mapped classes

I have this class:

class Payment(db.Model):
    __tablename__ = "payment"
    id = db.Column("payment_id", db.Integer, primary_key=True, autoincrement=True)
    date = db.Column("payment_date", db.DateTime)
    payment_collected = db.Column(db.Integer)
    amount_collected = db.Column(db.String(15))
    payment_type_id = db.Column("payment_type", db.Integer)
    reference_number = db.Column(db.String(255))
    is_invoice_data = db.Column(db.Integer)
    is_active = db.Column(db.Integer)
    payee_user_id = db.Column(db.Integer, db.ForeignKey("user.user_id"))
    services_rendered_id = db.Column(
        db.Integer, db.ForeignKey("services_rendered.service_id")
    )

which maps directly to a table in my database. The column payment_date (represented by the date property on the class) is set to default to CURRENT_TIMESTAMP. However, when calling this class as a constructor like:

new_payment = Payment(
    services_rendered_id=new_sr.id,
    payment_collected=True,
    payment_type_id=payment_type_id,
    payee_user_id=payee_id,
    amount_collected=amount_collected
)

the generated SQL inserts a value to ALL the map columns, including payment_date, and passes None for those columns that I do not specify in the constructor.

Example:

INSERT INTO 
    payment 
        (payment_date, payment_collected, amount_collected, payment_type, reference_number, is_invoice_data, is_active, payee_user_id, services_rendered_id) 
    VALUES 
        (None, 1, '258.40', '7', None, None, None, 3240, 28)

How could I avoid this behavior so that SQLAlchemy does not override the default values I've set in my database?

Upvotes: 0

Views: 87

Answers (1)

jwodder
jwodder

Reputation: 57600

Setting server_default=db.FetchedValue() for the date column will tell SQLAlchemy to get the default value for the column from the database upon INSERT. See the documentation for further information.

Upvotes: 1

Related Questions