Use Dash to Build to Web Apps on Azure Synapse Data

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

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

Connecting to Azure Synapse Data

Connecting to Azure Synapse 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.

Connecting to Azure Synapse

In addition to providing authentication (see below), set the following properties to connect to a Azure Synapse database:

• Server: The server running Azure. You can find this by logging into the Azure portal and navigating to Azure Synapse Analytics -> Select your database -> Overview -> Server name.
• Database: The name of the database, as seen in the Azure portal on the Azure Synapse Analytics page.

Authenticating to Azure Synapse

Connect to Azure Synapse using the following properties:

• User: The username provided for authentication with Azure.
• Password: The password associated with the authenticating user.

After installing the CData Azure Synapse Connector, follow the procedure below to install the other required modules and start accessing Azure Synapse 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 Azure Synapse 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.azuresynapse as mod
import plotly.graph_objs as go

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

cnxn = mod.connect("User=myuser;Password=mypassword;Server=localhost;Database=Northwind;")

Execute SQL to Azure Synapse

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, ProductName FROM Products WHERE ProductName = 'Konbu'", 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-azuresynapseedataplot'

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 Azure Synapse data and configure the app layout.

trace = go.Bar(x=df.Id, y=df.ProductName, 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='Azure Synapse Products 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 Azure Synapse data.

python azuresynapse-dash.py

Free Trial & More Information

Download a free, 30-day trial of the CData Python Connector for Azure Synapse to start building Python apps with connectivity to Azure Synapse 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.azuresynapse as mod
import plotly.graph_objs as go

cnxn = mod.connect("User=myuser;Password=mypassword;Server=localhost;Database=Northwind;")

df = pd.read_sql("SELECT Id, ProductName FROM Products WHERE ProductName = 'Konbu'", cnxn)
app_name = 'dash-azuresynapsedataplot'

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.ProductName, 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='Azure Synapse Products Data', barmode='stack')
		})
], className="container")

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