How to load table from SQLLite db file from PySpark?

Question

I am trying to load table from a SQLLite .db file stored at local disk. Is there any clean way to do this in PySpark?

Currently, I am using a solution that works but not as elegant. First I read the table using pandas though sqlite3. One concern is that during the process schema information is not passed (may or may not be a problem). I am wondering whether there is a direct way to load the table without using Pandas.

import sqlite3

import pandas as pd

db_path = 'alocalfile.db'

query = 'SELECT * from ATableToLoad'

conn = sqlite3.connect(db_path)

a_pandas_df = pd.read_sql_query(query, conn)

a_spark_df = SQLContext.createDataFrame(a_pandas_df)

There seems a way using jdbc to do this, but I have not figure out how to use it in PySpark.

Answer 1

1. Download the sqllite jdbc driver and provide the jar path below .  https://bitbucket.org/xerial/sqlite-jdbc/downloads/sqlite-jdbc-3.8.6.jar

pyspark --conf spark.executor.extraClassPath=<jdbc.jar> --driver-class-path <jdbc.jar> --jars <jdbc.jar> --master <master-URL>

2.Then read the sqlite database file into spark dataframe.

df = sqlContext.read.format('jdbc').\

     options(url='jdbc:sqlite:Chinook_Sqlite.sqlite',\

     dbtable='employee',driver='org.sqlite.JDBC').load()

df.printSchema() to see your schema.

If you wanted to know What is PySpark then visit this PySpark Tutorial.