flaskform selectfield choices not update or not getting refreshed

Question

I am facing an issue with the FlaskForm's selectField, which is not reading the db each time I visit "/product/add"

If I add a new category in the Category the choice of the selectField will not update the choice until I restart the server.

I would like for these to refresh every time I call the page.

Below is the code for my ProductForm.

class ProductForm(FlaskForm):
    allCategories = getCategoryList()

    category = SelectField('Category', validators = [DataRequired()], choices = [(category[0], category[1]) for category in allCategories ])
    product_name = StringField("Product Name", validators=[DataRequired()])
    product_description = StringField("Description", validators=[DataRequired()])

    submit = SubmitField("Save Product")

In past I solved this type of issue however there I was using flask_sqlalchemy, and using QuerySelectField I solved. Here I am using MySQl directly to connect, and not able to implement the same solution with it.