BI Engineer Interview Questions and Answers

I used a Random Forest classification model to build the project mentioned in my CV.

• Random Forest is an ensemble learning method that builds multiple decision trees and merges them together to get a more accurate and stable prediction.

• It is commonly used for classification tasks in machine learning.

• Random Forest can handle large data sets with higher dimensionality and is less prone to overfitting compared to a single decision tree model.

CTE is a temporary result set defined within a query, while temp table is a physical table created in tempdb for temporary storage.

• CTE stands for Common Table Expression and is defined within a query using the WITH keyword

• CTEs are mainly used for recursive queries, complex queries, or to improve readability of the query

• Temp tables are physical tables created in tempdb for temporary storage of data

• Temp tables are useful when you need to store intermediate results for further p...read more

Data validation processes ensure data accuracy and consistency.

• Performing range checks to ensure data falls within expected values

• Checking for data type consistency (e.g. ensuring a field is always a number)

• Validating data against predefined rules or constraints

• Identifying and handling missing or duplicate data

• Implementing data cleansing techniques to improve data quality

ETL processes involve extracting data from various sources, transforming it to fit business needs, and loading it into a target database.

• Extract data from multiple sources such as databases, files, APIs, etc.

• Transform the data by cleaning, filtering, aggregating, and structuring it.

• Load the transformed data into a target database or data warehouse.

• ETL tools like Informatica, Talend, and SSIS are commonly used for these processes.