Getting AttributeError: 'tuple' object has no attribute 'items' while creating a new item in flask sql alchemy in flask admin

Question

I have created two models in flask-sqlalchemy Product and Brand. Both have a relationship to each other. Whenever I try to create a brand I get the error AttributeError: 'tuple' object has no attribute 'items'.

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from datetime import datetime
from flask_admin import Admin
from flask_admin.contrib.sqla import ModelView


app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql+psycopg2://postgres:postgres@localhost:5432/ecommerce'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config['SECRET_KEY'] = 'secret'
db = SQLAlchemy(app)



# Models
class Brand(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), nullable=False, unique=True)
    products = db.relationship('Product', backref='brand', lazy=True)

    def __str__(self):
        return self.name

def format_products(view, context, model, name):
    return ', '.join([product.name for product in model.products])

class BrandView(ModelView):
    column_list = ['name', 'products']
    column_formatters = {'products': format_products}
    form_excluded_columns = ['products']

-

class Product(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(200), nullable=False)
    description = db.Column(db.Text)
    price = db.Column(db.Float, nullable=False)
    brand_id = db.Column(db.Integer, db.ForeignKey('brand.id'), nullable=False)



with app.app_context():
    db.create_all()

admin = Admin(app)
admin.add_view(ModelView(Product, db.session))
admin.add_view(BrandView(Brand, db.session))


@app.route('/')
def hello_world():
    return 'Hello World!'


if __name__ == '__main__':
    app.run()

I am not able to create a Brand.

Please edit the question to include the complete error traceback and the code that tries to create the brand. — snakecharmerb
– snakecharmerb, Commented Jun 11 at 8:46

Detlef · Accepted Answer · 2025-06-11 22:51:19Z

The problem is caused by the column name, which is declared as unique. For some time now, the resulting field_flags in wtforms are no longer assumed to be a tuple, but rather a dict. Unfortunately, Flask-Admin still uses the outdated version.

One possible solution is to create and integrate a custom form.

from flask_admin import form
from wtforms import StringField
from wtforms.validators import InputRequired, Length, ValidationError

# ...

class BrandForm(form.BaseForm):
    name = StringField('Name', validators=[
        InputRequired(), 
        Length(max=100)
    ])
    def validate_name(self, field):
        stmt = db.select(Brand).where(Brand.name == field.data)
        if db.session.execute(stmt).scalar(): 
            raise ValidationError('The name is already in use.')

class BrandView(ModelView):
    column_list = ['name', 'products']
    column_formatters = {'products': format_products}
    form = BrandForm

# ...

Collectives™ on Stack Overflow

Getting AttributeError: 'tuple' object has no attribute 'items' while creating a new item in flask sql alchemy in flask admin

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related