models.py

from datetime import datetime
from config import db, ma
from marshmallow import fields

class Person(db.Model):
    __tablename__ = "person"
    person_id = db.Column(db.Integer, primary_key=True)
    lname = db.Column(db.String(32))
    fname = db.Column(db.String(32))
    timestamp = db.Column(
        db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow
    )
    notes = db.relationship(
        "Note",
        backref="person",
        cascade="all, delete, delete-orphan",
        single_parent=True,
        order_by="desc(Note.timestamp)",
    )


class Note(db.Model):
    __tablename__ = "note"
    note_id = db.Column(db.Integer, primary_key=True)
    person_id = db.Column(db.Integer, db.ForeignKey("person.person_id"))
    content = db.Column(db.String(64), nullable=False)
    timestamp = db.Column(
        db.DateTime, default=datetime.utcnow, onupdate=datetime.utcnow
    )

class PersonSchema(ma.SQLAlchemyAutoSchema):
    class Meta:
        model = Person
        load_instance = True
    notes = fields.Nested('PersonNoteSchema', default=[], many=True)

class PersonNoteSchema(ma.SQLAlchemySchema):
    """
    This class exists to get around recursion issue
    """
    # def __init__(self, **kwargs):
    #     super().__init__(strict=True, **kwargs)

    note_id = fields.Int()
    person_id = fields.Int()
    content = fields.Str()
    timestamp = fields.Str()

class NoteSchema(ma.SQLAlchemyAutoSchema):
    # def __init__(self, **kwargs):
    #     super().__init__(strict=True, **kwargs)

    class Meta:
        model = Note
        load_instance = True

    person = fields.Nested("NotePersonSchema", default=None)

class NotePersonSchema(ma.SQLAlchemySchema):
    """
    This class exists to get around a recursion issue
    """
    # def __init__(self, **kwargs):
    #     super().__init__(strict=True, **kwargs)

    person_id = fields.Int()
    lname = fields.Str()
    fname = fields.Str()
    timestamp = fields.Str()