Dropdown of table names from a database

Dash Python
1

I’m trying to get my table_names from my database and make it as dropdown where I can click on it to show each tables graph but I don’t know how to call it.

I made this code but it comes out with this error
options=[{‘label’: i, ‘value’: i} for i in df.b.unique()]
NameError: name ‘df’ is not defined

can somebody tell me what I did wrong?
P.s : I’m a complete beginner in Python and coding in general.

import dash
import dash_core_components as dcc
import dash_html_components as html

import pandas as pd

import csv
import MySQLdb

import plotly.plotly as py
import plotly.graph_objs as go



conn = MySQLdb.connect(host='127.0.0.1', user='user', passwd='pass', db='road')
cursor = conn.cursor()

app = dash.Dash()

app.layout = html.Div([
    dcc.Dropdown(
        id='dropdown',
        options=[{'label': i, 'value': i} for i in df.unique()],
        value='x',
        clearable=False
    ),
    html.Div(id='graph-container')
])


@app.callback(
    dash.dependencies.Output('graph-container', 'children'),
    [dash.dependencies.Input('dropdown', 'value')])
def sql(value):
    dff = pd.read_sql(
        'SELECT * FROM  "{}"'.format(value),conn
        )
    return {
        'data': [
                    go.Scatter(
                        x=dff['time'],
                        y=dff['strain'],
                        mode='lines',
                        
                        ),
                ],
        'layout': go.Layout(

                    xaxis=dict(
        #               type='line',
                        title='Time(s)',
                        showgrid=True,
                        #zeroline=True,
                        showline=True,
                    ),
                    yaxis=dict(
                        title= 'Microstrain',
                        showgrid=True,
                        #zeroline=True,
                        showline=True,
                    ),
                    showlegend=False,
                )
        }


if __name__ == '__main__':
    app.run_server(debug=True)
1 Like
2

Exactly what it says. Variable df does not exist in the scope where it is called. You first have to create and initialize variable df before accessing it in

app.layout = html.Div([
    dcc.Dropdown(
        id='dropdown',
        options=[{'label': i, 'value': i} for i in df.unique()],
        value='x',
        clearable=False
    ),
    html.Div(id='graph-container')
])

What is it supposed to be?