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pythonmysqlflaskflask-peewee

Default value for peewee DoubleField doesn't get reflected in MySQL db

Use case: Want to store 0.0 as default value while no value is passed for a pewee's DoubleField. I wrote following code but didn't work for me.

class MyRelation(peewee.Model):
    id = peewee.PrimaryKeyField()
    percentage = peewee.DoubleField(default=0.0)

Here is an api

@api_blueprint.route('/add_data', methods=['POST'])
@http_header
def add_data():
    try:
        incoming = json.loads(request.data)
        data = MyRelation(percentage=incoming["percentage"])
        data.save()

        return success_response(201,"Data has been inserted :)")

    except Exception as e:
        log(str(e))
        return raise_error(500, str(e))

which logs following error

10-05-17 05:24:51 Line:199  Message: Error in add_data(),views.api: (1048, "Column 'percentage' cannot be null")
Solution

  • The difference is only enforced on the Python side -- so if you're expecting the server to enforce the default you'll need to use a constraint:

    percentage = peewee.DoubleField(constraints=[SQL('DEFAULT 0.0')])

    Docs: http://docs.peewee-orm.com/en/latest/peewee/models.html#default-field-values