modelos.py

class Cliente:
    tabela = "clientes"
    def __init__(self, id=None, nome="", telefone="", email=""):
        self.id = id
        self.nome = nome
        self.telefone = telefone
        self.email = email
        
    def save(self, con, tabela=""):
        
        if not self.id:
            con.execute("""INSERT INTO {tabela} 
                    ('nome', 'telefone', 'email') 
                    VALUES(?, ?, ?) """.format(tabela=(tabela if tabela else self.tabela)),
                    (self.nome, self.telefone, self.email))
        else:
            con.execute("""
                UPDATE {tabela} SET
                nome=?, telefone=?, email=?
                WHERE id=?
            """.format(tabela=(tabela if tabela else self.tabela)),
                    (self.nome, self.telefone, self.email, self.id))
        con.commit()

    @classmethod
    def load(cls, id, con, tabela=""):
        cursor = con.execute("""SELECT id, nome, telefone, email  FROM {tabela} WHERE id=?""".format(tabela=(tabela if tabela else cls.tabela)), (id,))
        dados = cursor.fetchall()[0]
        cliente = Cliente(*dados)
        return cliente
    
    @classmethod
    def last_id(cls, con, tabela=""):
        response = con.execute("""SELECT MAX(id) FROM {tabela}""".format(tabela=(tabela if tabela else cls.tabela))).fetchall()[0][0]
        return response if response is not None else 0
        
        
    @classmethod
    def cria_tabela(cls, con, tabela=""):
        con.execute("""CREATE TABLE IF NOT EXISTS
            {tabela}
            (id integer primary key autoincrement,
             nome char,
             telefone char,
             email char
            )
        """.format(tabela=(tabela if tabela else cls.tabela)))
        
    @classmethod
    def campos(cls):
        return [
        {'name': 'nome', 'label': 'Nome', 'type': str},
        {'name': 'telefone', 'label': 'Telefone', 'type': str},
        {'name': 'email', 'label': 'E-mail', 'type': str},
    ]  
    
    def __repr__(self):
        return "<Cliente '{}', {}, {}>".format(self.nome, self.telefone, self.email)
    

registro_config.py

config = [
    {'fieldname': 'Cliente', 'type': str},
    {'fieldname': 'Telefone', 'type': str},
    {'fieldname': 'E-mail', 'type': str},
    {'fieldname': 'nome do pet', 'type': str},
    {'fieldname': 'telefone do pet'}
]  

registros.py

import csv
import os
import sqlite3
import tkinter

import modelos
from modelos import Cliente

FILENAME = "exemplo.db"

#    global name, age, address, phone, email, index

#from registro_config import config 

variaveis = {}


def init():
    global con
    con = sqlite3.connect(FILENAME)
    Cliente.cria_tabela(con)

def save():
    update()
    cliente.save(con)
        
def load():
    global cliente
    try:
        cliente = Cliente.load(index, con)
    except IndexError:
        cliente = Cliente()
    
        
def create_field(window, label):
    f1 = tkinter.Frame(window)
    f1.pack()
    variable = tkinter.Variable(window)
    l1 = tkinter.Label(f1, text=label)
    e1 = tkinter.Entry(f1, textvariable=variable)
    l1.pack(side="left")
    e1.pack(side="left")
    return variable

def next():
    global index
    index += 1
    if index >= Cliente.last_id(con):
        index = 1
    load()
    show()
    
def previous():
    global index
    index -= 1
    if index < 1:
        index = Cliente.last_id(con)
    load()
    show()

def new():
    global index, cliente
    index = Cliente.last_id(con) + 1
    cliente = Cliente()
    show()

def add_button(frame, t, command, side="left"):
    button = tkinter.Button(frame, text=t, command=command)
    button.pack(side="left")

def warn_user(message):
    status_line["text"] = message
    status_line["fg"] = "red"

def show():
    global index, cliente
    print(cliente)
    for field in Cliente.campos():
        var = variaveis[field["name"]]
        name = field["name"]
        var.set(getattr(cliente, name))
        
    status_line["text"] = str(index)
    status_line["fg"] = "black"

def update():
    for field in Cliente.campos():
        var = variaveis[field["name"]]
        name = field["name"]
        setattr(cliente, name, var.get())

def main():
    global index, status_line
    window = tkinter.Tk()
    for field in Cliente.campos():
        variaveis[field['name']] = create_field(window, field['label'])
    
    f3 = tkinter.Frame(window)
    f3.pack()
    add_button(f3, "<<", previous)
    add_button(f3, "Salvar", save)
    add_button(f3, "Novo", new)
    add_button(f3, ">>", next, side="right")
    
    status_line = tkinter.Label(window)
    status_line.pack()
    
    index = 1
    load()
    show()
    
    tkinter.mainloop()

if __name__ == "__main__":
    init()
    main()

registroweb.py

import datetime
import sqlite3
import threading

from flask import Flask, request, redirect
# from flask_sqlalchemy import SQLAlchemy
from jinja2 import Template

from modelos import Cliente

app = Flask(__name__)

connections = {}

def get_con():
    thread = threading.current_thread()
    if thread not in connections:
        connections[thread] = sqlite3.connect("../exemplo.db")
    return connections[thread]

def init():
    Cliente.cria_tabela(get_con())

# init()

@app.route("/")
def hello_world():
    total_clientes = Cliente.last_id(get_con())
    clientes = [Cliente.load(id, get_con()) for id in range(1, total_clientes + 1)]
    template =  Template("""
<h1>Clientes</h1>
<a href="novo">Inserir novo cliente</a><br>
<ul>
{% for cliente in clientes %}
    <li> 
       <a href="editar/{{ cliente.id }}">
       {{ cliente.nome }}
       </a>, {{ cliente.telefone }}, {{ cliente.email }}
    </li>
{% endfor %}
</ul>

""")
    return template.render(clientes=clientes)


@app.route("/novo", methods=["GET", "POST"])
def novo():
    if request.method == "GET":
        template = Template("""
        <h1> Novos dados para {{ nome }}</h1>
        <form action="#" method="POST">
        {% for campo in campos %}
        {{ campo.label }}: <input type="entry" name="{{ campo.name }}"><br>
        {% endfor %}
        <input type="submit" value="Salvar">
        </form>
        """)
        return template.render(campos=Cliente.campos(), nome="Cliente")
    elif request.method == "POST":
        form = request.form
        cliente = Cliente(nome=form["nome"], telefone=form["telefone"], email=form["email"])
        cliente.save(get_con())
        return redirect("/")
        
@app.route("/editar/<int:id>", methods=["GET", "POST"])
def editar(id):
    if request.method == "GET":
        cliente = Cliente.load(id, get_con())
        template = Template("""
        <h1> Novos dados para {{ nome }}</h1>
        <form action="#" method="POST">
        <input type="hidden" name="cliente_id" value="{{ dados["id"] }}" >
        {% for campo in campos %}
        {{ campo.label }}: <input type="entry" name="{{ campo.name }}" value="{{ dados[campo.name] }}"><br>
        {% endfor %}
        <input type="submit" value="Salvar">
        </form>
        """)
        return template.render(campos=Cliente.campos(), nome=cliente.nome, dados=cliente.__dict__)
    elif request.method == "POST":
        form = request.form
        cliente = Cliente(nome=form["nome"], telefone=form["telefone"], email=form["email"])
        cliente.id = form["cliente_id"]
        cliente.save(get_con())
        return redirect("/")