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

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

Connecting to xBase Data

Connecting to xBase 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 DataSource property must be set to the name of the folder that contains the .dbf files. Specify the IncludeFiles property to work with xBase table files having extensions that differ from .dbf. Specify multiple extensions in a comma-separated list.

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

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

cnxn = mod.connect("DataSource=MyDBFFilesFolder;")

Execute SQL to xBase

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 Company, Total FROM Invoices WHERE Class = 'ASSET'", 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-xbaseedataplot'

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 xBase data and configure the app layout.

trace = go.Bar(x=df.Company, y=df.Total, name='Company')

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='xBase Invoices 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 xBase data.

python xbase-dash.py

Free Trial & More Information

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

cnxn = mod.connect("DataSource=MyDBFFilesFolder;")

df = pd.read_sql("SELECT Company, Total FROM Invoices WHERE Class = 'ASSET'", cnxn)
app_name = 'dash-xbasedataplot'

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.Company, y=df.Total, name='Company')

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='xBase Invoices Data', barmode='stack')
		})
], className="container")

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