H&R Block Data Engineer Interview Questions and Answers

An index is a data structure that improves the speed of data retrieval operations in a database.

• Types of indexes include clustered index, non-clustered index, unique index, and composite index.

• Indexes can be created on one or multiple columns in a table.

• Indexes help in quickly locating data without having to scan the entire table.

• Examples of indexes are primary key indexes, foreign key indexes, and secondary indexes.

SCD stands for Slowly Changing Dimension, which is a concept used in data warehousing to track changes in data over time.

• SCD Type 1: Overwrites old data with new data, losing historical information.

• SCD Type 2: Keeps multiple versions of the same record, each with a different timestamp.

• SCD Type 3: Maintains separate columns for current and previous values, limiting historical data tracking.

• SCD Type 4: Uses separate hist...read more

Data pipeline is a series of processes that collect, transform, and load data from various sources to a destination for analysis.

• Data ingestion: Collecting data from various sources like databases, APIs, logs, etc.

• Data processing: Cleaning, transforming, and enriching the data to make it usable for analysis.

• Data storage: Storing the processed data in a data warehouse, data lake, or other storage solutions.

• Data analysis...read more