Can a simple CRUD app be made with streamlit?

Using Streamlit
,
3

Hi @pybokeh

I see three issues with accepting user input to write to a database

  1. only connecting to the database once
  2. waiting for input data to be fully provided
  3. clearing input fields on submit

Regarding 1, this would be a good use case for the @cache decorator, as you could cache your database connection so it’s only initialized once.

If you try to do this now you’ll probably encounter an error saying cannot cache database client or something similar.

This should be fixed with https://github.com/streamlit/streamlit/issues/551 which is currently being worked on.

As a workaround you could do something like this

import streamlit as st
from pymongo import MongoClient

if not hasattr(st, "client"):
    st.client = MongoClient('mongodb://127.0.0.1/local')
collection = st.client.local.user

name = st.text_input('name')
if name:
    collection.insert_one({'name': name})

st.write(list(collection.find()))

Regarding 2, this is not currently possible but is being discussed at Have a widget not trigger an immediate update?

Regarding 3, if you reload the report after inputting data a second record will be inserted, as the widgets maintain their state, so you’ll probably want to clear the inputs after inserting.

This is not currently possible but is being discussed at https://github.com/streamlit/streamlit/issues/623

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