HCLTech ETL Developer Interview Questions and Answers

The greatest challenge faced during migration to cloud from on-premise DB is ensuring data security and compliance.

• Ensuring data security during transit and at rest

• Maintaining compliance with regulations and industry standards

• Minimizing downtime and ensuring data integrity

• Optimizing performance and cost efficiency in the cloud environment

ETL is Extract, Transform, Load where data is extracted, transformed, and loaded into a data warehouse. ELT is Extract, Load, Transform where data is extracted, loaded into a data warehouse, and then transformed.

• ETL involves extracting data from source systems, transforming it according to business rules, and loading it into a data warehouse.

• ELT involves extracting data from source systems, loading it into a data wareh...read more

Loads in Informatica refer to the process of moving data from source to target in a data warehouse.

• Loads involve extracting data from source systems

• Transforming the data as needed

• Loading the data into the target data warehouse or database

• Loads can be full, incremental, or delta depending on the requirements

• Example: Loading customer data from a CRM system into a data warehouse for analysis

Use GROUP BY and HAVING clause to find duplicates in a table.

• Use GROUP BY to group rows with same values together

• Use HAVING COUNT(*) > 1 to filter out duplicates

• Example: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > 1;