Ecolab Azure Data Engineer Interview Questions and Answers

The output after inner join of table 1 and table 2 will be 2,3,5.

• Inner join only includes rows that have matching values in both tables.

• Values 2, 3, and 5 are present in both tables, so they will be included in the output.

• Null values are not considered as matching values in inner join.

The project involves building a data pipeline to ingest, process, and analyze large volumes of data from various sources in Azure.

• Utilizing Azure Data Factory for data ingestion and orchestration

• Implementing Azure Databricks for data processing and transformation

• Storing processed data in Azure Data Lake Storage

• Using Azure Synapse Analytics for data warehousing and analytics

• Leveraging Azure DevOps for CI/CD pipeline aut

Designing an effective ADF pipeline involves considering various metrics and factors.

• Understand the data sources and destinations

• Identify the dependencies between activities

• Optimize data movement and processing for performance

• Monitor and track pipeline execution for troubleshooting

• Consider security and compliance requirements

• Use parameterization and dynamic content for flexibility

• Implement error handling and retries fo

Activities in Azure Data Factory (ADF) are the building blocks of a pipeline and perform various tasks like data movement, data transformation, and data orchestration.

• Activities can be used to copy data from one location to another (Copy Activity)

• Activities can be used to transform data using mapping data flows (Data Flow Activity)

• Activities can be used to run custom code or scripts (Custom Activity)

• Activities can be u...read more

Dataframes in pyspark are distributed collections of data organized into named columns.

• Dataframes are similar to tables in a relational database, with rows and columns.

• They can be created from various data sources like CSV, JSON, Parquet, etc.

• Dataframes support SQL queries and transformations using PySpark functions.

• Example: df = spark.read.csv('file.csv')

I connect onPrem to Azure using Azure ExpressRoute or VPN Gateway.

• Use Azure ExpressRoute for private connection through a dedicated connection.

• Set up a VPN Gateway for secure connection over the internet.

• Ensure proper network configurations and security settings.

• Use Azure Virtual Network Gateway to establish the connection.

• Consider using Azure Site-to-Site VPN for connecting onPremises network to Azure Virtual Network.

Autoloader in Databricks is a feature that automatically loads new data files as they arrive in a specified directory.

• Autoloader monitors a specified directory for new data files and loads them into a Databricks table.

• It supports various file formats such as CSV, JSON, Parquet, Avro, and ORC.

• Autoloader simplifies the process of ingesting streaming data into Databricks without the need for manual intervention.

• It can be ...read more

Json data normalization involves structuring data to eliminate redundancy and improve efficiency.

• Identify repeating groups of data

• Create separate tables for each group

• Establish relationships between tables using foreign keys

• Eliminate redundant data by referencing shared values

Polybase is a feature in Azure SQL Data Warehouse that allows users to query data stored in Hadoop or Azure Blob Storage.

• Polybase enables users to access and query external data sources without moving the data into the database.

• It provides a virtualization layer that allows SQL queries to seamlessly integrate with data stored in Hadoop or Azure Blob Storage.

• Polybase can significantly improve query performance by levera...read more

Use DISTINCT keyword in SQL to remove duplicates from a dataset.

• Use SELECT DISTINCT column_name FROM table_name to retrieve unique values from a specific column.

• Use SELECT DISTINCT * FROM table_name to retrieve unique rows from the entire table.

• Use GROUP BY clause with COUNT() function to remove duplicates based on specific criteria.