Use Dash to Build to Web Apps on SAP HANA 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 SAP HANA, the pandas module, and the Dash framework, you can build SAP HANA-connected web applications for SAP HANA data. This article shows how to connect to SAP HANA with the CData Connector and use pandas and Dash to build a simple web app for visualizing SAP HANA data.

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

Connecting to SAP HANA Data

Connecting to SAP HANA 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.

Set the Server, Database and Port properties to specify the address of your SAP Hana database to interact with. Set the User and the Password properties to authenticate to the server.

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

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

cnxn = mod.connect("User=system;Password=mypassword;Server=localhost;Database=systemdb;")

Execute SQL to SAP HANA

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 Name, OwnerId FROM Buckets WHERE Name = 'TestBucket'", 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-saphanaedataplot'

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 SAP HANA data and configure the app layout.

trace = go.Bar(x=df.Name, y=df.OwnerId, name='Name')

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='SAP HANA Buckets 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 SAP HANA data.

python saphana-dash.py

Free Trial & More Information

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

cnxn = mod.connect("User=system;Password=mypassword;Server=localhost;Database=systemdb;")

df = pd.read_sql("SELECT Name, OwnerId FROM Buckets WHERE Name = 'TestBucket'", cnxn)
app_name = 'dash-saphanadataplot'

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.Name, y=df.OwnerId, name='Name')

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='SAP HANA Buckets Data', barmode='stack')
		})
], className="container")

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