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Use Dash to Build to Web Apps on Data

The CData Python Connector for enables you to create Python applications that use pandas and Dash to build -connected web apps.

The rich ecosystem of Python modules lets you get to work quickly and integrate your systems more effectively. With the CData Python Connector for , the pandas module, and the Dash framework, you can build -connected web applications for data. This article shows how to connect to with the CData Connector and use pandas and Dash to build a simple web app for visualizing data.

With built-in, optimized data processing, the CData Python Connector offers unmatched performance for interacting with live data in Python. When you issue complex SQL queries from , the driver pushes supported SQL operations, like filters and aggregations, directly to and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations).

Connecting to Data

Connecting to data looks just like connecting to any relational data source. Create a connection string using the required connection properties. For this article, you will pass the connection string as a parameter to the create_engine function.

The primary method for performing basic authentication is to provide your login credentials, as follows:

  • User: Set this to your username.
  • Password: Set this to your password.

Optionally, if you are making use of a sandbox environment, set the following:

  • UseSandbox: Set this to true if you are authenticating with a sandbox account.

Authenticating Using Account Number and License Key

Alternatively, you can authenticate using your account number and license key. Connect to data using the following:

  • AccountId: Set this to your Account Id. The Account Id is listed in the upper right hand corner of the admin console.
  • LicenseKey: Set this to your Avalara Avatax license key. You can generate a license key by logging into Avalara Avatax as an account adminstrator and navigating to Settings -> Reset License Key.

After installing the CData Connector, follow the procedure below to install the other required modules and start accessing through Python objects.

Install Required Modules

Use the pip utility to install the required modules and frameworks:

pip install pandas
pip install dash
pip install dash-daq

Visualize Data in Python

Once the required modules and frameworks are installed, we are ready to build our web app. Code snippets follow, but the full source code is available at the end of the article.

First, be sure to import the modules (including the CData Connector) with the following:

import os
import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import cdata.avalaraavatax as mod
import plotly.graph_objs as go

You can now connect with a connection string. Use the connect function for the CData Connector to create a connection for working with data.

cnxn = mod.connect("User=MyUser;Password=MyPassword;")

Execute SQL to

Use the read_sql function from pandas to execute any SQL statement and store the result set in a DataFrame.

df = pd.read_sql("SELECT Id, TotalTax FROM Transactions WHERE Code = '051349'", cnxn)

Configure the Web App

With the query results stored in a DataFrame, we can begin configuring the web app, assigning a name, stylesheet, and title.

app_name = 'dash-avalaraavataxedataplot'

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.title = 'CData + Dash'

Configure the Layout

The next step is to create a bar graph based on our data and configure the app layout.

trace = go.Bar(x=df.Id, y=df.TotalTax, name='Id')

app.layout = html.Div(children=[html.H1("CData Extension + Dash", style={'textAlign': 'center'}),
	dcc.Graph(
		id='example-graph',
		figure={
			'data': [trace],
			'layout':
			go.Layout(title=' Transactions Data', barmode='stack')
		})
], className="container")

Set the App to Run

With the connection, app, and layout configured, we are ready to run the app. The last lines of Python code follow.

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

Now, use Python to run the web app and a browser to view the data.

python avalaraavatax-dash.py

Free Trial & More Information

Download a free, 30-day trial of the Python Connector to start building Python apps with connectivity to data. Reach out to our Support Team if you have any questions.



Full Source Code

import os
import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import cdata.avalaraavatax as mod
import plotly.graph_objs as go

cnxn = mod.connect("User=MyUser;Password=MyPassword;")

df = pd.read_sql("SELECT Id, TotalTax FROM Transactions WHERE Code = '051349'", cnxn)
app_name = 'dash-avalaraavataxdataplot'

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.title = 'CData + Dash'
trace = go.Bar(x=df.Id, y=df.TotalTax, name='Id')

app.layout = html.Div(children=[html.H1("CData Extension + Dash", style={'textAlign': 'center'}),
	dcc.Graph(
		id='example-graph',
		figure={
			'data': [trace],
			'layout':
			go.Layout(title=' Transactions Data', barmode='stack')
		})
], className="container")

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