The connector can be used to create ETL applications and pipelines for CSV data in Python using Petl.

Install Required Modules

Install the Petl modules using the pip utility.

pip install petl

Connecting

After you import the modules, including the CData Python Connector for Parquet, you can use the connector's connect function to create a connection using a valid Parquet connection string. If you prefer not to use a direct connection, you can use a SQLAlchemy engine.

import petl as etl
import cdata.parquet as mod
cnxn = mod.connect("URI=C:\folder\table.parquet;")

Extract, Transform, and Load the Parquet Data

Create a SQL query string and store the query results in a DataFrame.

sql = "SELECT	Id, Column1 FROM SampleTable_1 "
table1 = etl.fromdb(cnxn,sql)

Loading Data

With the query results stored in a DataFrame, you can load your data into any supported Petl destination. The following example loads the data into a CSV file.

etl.tocsv(table1,'output.csv')

Modifying Data

Insert new rows into Parquet tables using Petl's appenddb function.

table1 = [['Id','Column1'],['Jon Doe','John']]
etl.appenddb(table1,cnxn,'SampleTable_1')