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Wednesday 19 July 2023

modularize your PySpark code that includes SQL queries based on createOrReplaceTempView

 To modularize your PySpark code that includes SQL queries based on createOrReplaceTempView, you can follow a few steps:

Create separate Python modules for different components of your code.

Define functions in each module to encapsulate the logic related to specific SQL queries and transformations.

Import the necessary modules and call the functions in your main code.

In this example, the create_temp_views function in queries.py encapsulates the logic to read CSV files, create temporary views using createOrReplaceTempView, and perform a join operation. By separating the SQL-related code into a separate module, you can easily reuse and maintain your queries.

Note that you need to replace the file paths and SQL queries in the example with your specific requirements. Additionally, you might need to adjust the imports and customize the functions according to your actual codebase.

Create a module named queries.py to define functions for your SQL queries:

# queries.py

from pyspark.sql import SparkSession

def create_temp_views(spark):

    # Register temp views using createOrReplaceTempView

    df1 = spark.read.csv("data/file1.csv", header=True)

    df1.createOrReplaceTempView("table1")

    df2 = spark.read.csv("data/file2.csv", header=True)

    df2.createOrReplaceTempView("table2")

    df3 = spark.sql("SELECT * FROM table1 JOIN table2 ON table1.id = table2.id")

    df3.createOrReplaceTempView("table3")

    # Return the SparkSession for further use, if needed

    return spark


Create your main script and import the queries module to call the functions:

# main.py

from pyspark.sql import SparkSession

import queries

# Create a SparkSession

spark = SparkSession.builder.appName("Modularized PySpark").getOrCreate()

# Call the create_temp_views function from queries module

spark = queries.create_temp_views(spark)

# Use the registered temp views for further processing

result = spark.sql("SELECT * FROM table3")

result.show()

# Stop the SparkSession

spark.stop()