The Most Common Data Warehouse Interview Questions and Answers

When applying for a job as a business intelligence analyst, data engineer, or other related role, interviewers may ask you questions about data warehousing to gauge your knowledge of the process. You can effectively prepare for a job interview by reading some common questions that employers may ask about data warehouses. This preparation can help you make a positive impression on potential employers during an interview.

In this article, we list 61 data warehouse interview questions, including six with sample answers, to help you effectively prepare for your next job interview.

06 Data Warehouse Interview Questions with Model Answers

Review these data warehouse interview questions and sample answers to help you prepare for your job interview:

1. What is business intelligence?

Interviewers may ask this question to assess your ability to use data to make informed business decisions. Business intelligence refers to the ways you can use a data warehouse to collect, integrate, and analyze information. In your answer, provide a clear definition of business intelligence and explain why it is important to properly catalog this data.

Example: “Business intelligence is the use of data to gain insight into sales, productivity or growth. A decision support system or DSS can help you properly collect business data to analyze and integrate information as needed. Businesses can use this data to make strategic decisions about growth of their sales and operations.”

2. What is the difference between a data warehouse and an operational database?

An employer may ask this question to determine your knowledge of databases and how to use them. When answering this question, define each database. Then explain how the purpose of each database differs to show your knowledge of both systems.

Example: “The key difference between a data warehouse and an operational database is the way the stored data is used. Data warehouses are central repositories containing processed data about a company. They catalog data for future use. Operational databases provide information about business transactions and a data warehouse. They contain data that a company or the organization uses on a daily basis.”

3. What is a data warehouse dimension and what is its function?

Employers ask this question to understand how well you know dimensions. In data warehouses, a dimension refers to a classification or catalog that stores data for future reference. In your answer, define the term and explain why dimensions are important in a data warehouse.

Example: “A dimension is a collection or group of data. They allow systematic storage of data in a data warehouse. For example, you can store all client information under the ‘clients’ dimension.” This organization can facilitate data retrieval in the future.”

4. Can you explain the different types of data markets?

Data marts can help teams or managers quickly access data, so interviewers can ask this question to see how you can use this tool in your organization. You can usually create a data mart for a specific department to store their data. Answer this question by explaining the three primary types of data markets: dependent, independent, and hybrid.

Example: “There are three main types of data marts, which are dependent, independent and hybrid. Dependent data marts provide a centralized source of data because they receive information from existing data warehouses. Independent data marts are suitable for organizations that require more divisional data because they contain information from external sources. Hybrid data marts allow a team or organization to access both existing data warehouses and external sources of their data.”

5. Do you recommend using multidimensional OLAP or relational OLAP if the company uses tables for data?

The interviewer may ask this question to assess your experience using online analytical processing (OLAP) tools to store and organize data. They may also ask this question to see if you understand the organization’s data needs. Select the method you recommend and clearly state why you have chosen that system.

Example: “While relational OLAP stores data in a relational database, multidimensional OLAP stores information in a cube compatible with popular spreadsheets. Multidimensional OLAP provides easier communication for these applications between the two storage options. For this reason, I recommend using multidimensional OLAP over relational OLAP.”

6. What are the benefits of using a data warehouse?

Employers may ask this question to see if you can help the company use a data warehouse to achieve its organizational goals. Choose two or three benefits of using data warehouses to highlight in your answer. For each benefit, provide a clear explanation of how it can help the business make informed decisions.

Example: “A few benefits of data warehouses include increased efficiency, lower operating costs, and better decision making. If a data warehouse has clear and consistent procedures for labeling its dimensions, you can easily find and analyze data. Businesses can make important decisions using all available information by quickly locating that data .In addition, a single, well-organized data warehouse saves the organization money by keeping all data in a central location.”

Interview Questions about Data Warehouse Experience and Background

Questions about your experience using data warehouses can give the interviewer more information about how your education and background prepared you for the open position. These questions may include:

1.       What is your highest education?

2.       What was your major in college?

3.       How did you become interested in data warehouses?

4.       What qualifications do you have for this position?

5.       What experience do you have with using structured query language (SQL)?

6.       How did your last position prepare you for this job?

7.       Are you satisfied with using the text editor?

8.       What experience do you have with computer programming?

9.       What programming languages ​​do you know?

10.   Are you comfortable leading a team?

11.   How do you communicate with others who may not understand technical terms or concepts?

12.   What is your level of knowledge of data warehouse terminology?

13.   What is the largest data set you have processed in your career?

14.   What have you done to learn a new technical skill or concept in the last year?

15.   What is your greatest career achievement?

16.   What types of dimensional modeling have you used in other positions?

17.   What tools did you use for the Extract, Transform and Load (ETL) processes?

18.   Have you ever made a mistake while working with a data warehouse and what did you learn from it?

In-Detail Interviews about Data Storage

Employers may ask interview questions for a business intelligence or data analysis role to assess your analytical and problem-solving skills.

Here are some examples of detailed questions you may receive about the data warehouse:

1.       Can you list five ways to use data warehouses?

2.       What are the costs of data mining?

3.       Can you compare and contrast the use of a star diagram with a snowflake diagram?

4.       What steps will you take when building a data warehouse?

5.       What are the most important responsibilities of a data warehouse manager?

6.       What is the difference between a database and a data warehouse?

7.       What is the difference between the Kimball philosophy and the Inmon data warehouse philosophy?

8.       How does data analytics apply to data warehouses?

9.       What is the difference between OLAP and OLTP?

10.   How many types of OLAP servers are there and what are the differences between them?

11.   Can you describe three applications of a data warehouse?

12.   What are the stages of the data warehouse delivery process?

13.   What are the advantages of using aggregate tables?

14.   What steps do you take to retrieve the time dimension?

15.   When can you use an entity relationship diagram?

16.   Can you describe the layered architecture of the ETL cycle?

17.   How often do you recommend data cleaning and why?

18.   How many dimensions does a cube operation use?

19.   What is incisional surgery?

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