User-created Record Fields

I am creating a web-app w/ Flask + Flask-WTF that has CRM-like features as a project. My current database (MongoDB) structure is I have:

1. Users who can login,
2. People who are assigned to users, and
3. Records who are assigned to people.

People have various fields to be filled out (Name, Phone Number, Email, etc).

I want Users to be able to create custom fields for people. I am trying to plan out how to implement this from a database design perspective. My initial thoughts are to:

1. For each field created, add a new field without a value for each People assigned to the user.
2. Use a for-loop to dynamically create the form class by looping through each field-value in my database and excluding non-required ones.
3. Use a for-loop to dynamically output the web form by looping through each field-value in my database and excluding non-required ones.

Another idea I have is:

1. For each field created, add the custom field, with a parentRecord equal to the User ID to a new MongoDB collection.
2. Use a for-loop to create the form class & web form dynamically, but I wouldn’t need to exclude non-required ones as the only fields in the collection would be the custom ones, and wouldn’t include any special data points that don’t get displayed.

So my questions are:

1. Will my ideas above work?
2. Which one is better?
3. Is there a better way?

Answer

I decided to create a customfields MongoDB collection that has a parentRecord as the User.

I faced a few challenges:

1. I had to dynamically create a form via flask WTF. I ended up using wtforms_dynamic_fields to accomplish this. I then used a for-loop to dynamically generate each form in Jinja. I simply queried the customfields DB where the parentRecord matched the logged in User, and then created custom fields based upon the values saved in customfields.

2. The second issue I faced was getting the data from the submitted form and then building a MongoDB-friendly list to insert a new record with when creating new record. This was accomplished by using request.form.items() and iterating through them and using list.update() to add all of my required fields to a list.