TCS Data Engineer Interview Questions, Process, and Tips

CTE stands for Common Table Expression in SQL, used to create temporary result sets that can be referenced within a query.

• CTEs improve readability and maintainability of complex queries

• They can be recursive, allowing for hierarchical data querying

• CTEs are defined using the WITH keyword followed by the CTE name and query

MERGE statement is used to perform insert, update, or delete operations in a single statement based on a condition.

• Combines INSERT, UPDATE, and DELETE operations into a single statement

• Helps to avoid multiple separate statements for different operations

• Useful for synchronizing data between two tables based on a condition

To call a notebook from another notebook in Databricks, use the %run command followed by the path of the notebook.

• Use the %run command followed by the path of the notebook to call it from another notebook.

• Make sure the notebook you want to call is in the same workspace or accessible to the notebook you are calling it from.

• You can also pass parameters to the notebook being called using the %run command.

Datastage and Informatica are both ETL tools used for data integration, but they have differences in terms of features and capabilities.

• Datastage is developed by IBM and is known for its parallel processing capabilities, while Informatica is developed by Informatica Corporation and is known for its strong data quality features.

• Datastage has a more user-friendly interface compared to Informatica, making it easier for be...read more

Hashing is a technique used to convert data into a fixed-size string of bytes.

• Hash functions are used to map data of arbitrary size to fixed-size values.

• Common hashing algorithms include MD5, SHA-1, and SHA-256.

• Hashing is commonly used in data security, password storage, and data retrieval.

Answers to interview questions for Data Engineer position.

• 1. Partitioning is a way to divide a large dataset into smaller, more manageable parts based on a specific column or expression. Bucketing is a technique to further organize the data within each partition into smaller, equally-sized files based on a hash function.

• 2. UNION combines the result sets of two or more SELECT statements, removing duplicate rows. UNION A...read more