HCLTech ETL Lead Interview Questions and Answers

ETL Developers are responsible for designing, developing, and maintaining ETL processes to extract, transform, and load data from various sources into a data warehouse.

• Designing ETL processes to extract data from multiple sources

• Transforming data to meet business requirements

• Loading data into a data warehouse or other target systems

• Developing and maintaining ETL jobs using tools like Informatica, Talend, or SSIS

SCD Type 1 in IICS involves overwriting existing data with new data without maintaining historical changes.

• In IICS, use the Mapping Designer to create a mapping that loads data from source to target.

• Use a Lookup transformation to check if the record already exists in the target table.

• If the record exists, update the existing record with new data using an Update Strategy transformation.

• If the record does not exist, inse...read more

Analytical functions are used to perform calculations across a set of rows related to the current row.

• Analytical functions operate on a group of rows and return a single result for each row

• They can be used to calculate running totals, moving averages, rank, percentiles, etc.

• Examples include ROW_NUMBER(), RANK(), SUM() OVER(), AVG() OVER()

The Slowly Changing Dimension Type 2 (SCD2) transformation is used for handling historical data changes in a data warehouse.

• SCD2 transformation is used to track historical changes in dimension tables.

• It maintains multiple versions of a record by adding new rows with updated information and end-dating the previous record.

• Commonly used in scenarios where historical data needs to be preserved and queried.

• Example: When a c...read more

To find the count of different types of joins between two tables A and B.

• Left join: Includes all records from table A and matching records from table B.

• Right join: Includes all records from table B and matching records from table A.

• Inner join: Includes only the matching records from both tables.

• Full outer join: Includes all records when there is a match in either table A or table B.

DBA stands for Database Administrator. The architecture of DBA involves managing and maintaining databases to ensure data integrity and security.

• DBA is responsible for installing, configuring, and upgrading database software.

• They monitor database performance and troubleshoot issues.

• DBA designs and implements backup and recovery strategies to prevent data loss.

• They also manage user access and security permissions within...read more

Maintaining the database involves regular monitoring, performance tuning, applying patches, and ensuring backups are taken regularly.

• Regularly monitor database performance and usage

• Perform routine maintenance tasks such as applying patches and updates

• Take regular backups to ensure data integrity and disaster recovery

• Implement security measures to protect the database from unauthorized access

• Optimize database performanc

I joined inm because of the company's reputation for innovation and growth in the tech industry.

• Attracted to company's reputation for innovation

• Excited about opportunities for growth in tech industry

• Impressed by company culture and values