Data Warehouse Interview Questions and Answers (updated 2023)

Data Warehouse Interview Questions and Answers

Data warehouse interview questions and answers are helpful at the time of giving an interview on big data or ETL. Data warehouse is used in multiple companies where we use big data. While giving the interview on ETL technology data warehouse tools, questions and answers are very helpful. At the time of applying for the post of ETL then, we need to prepare the question and answer of data warehouse technology.

Introduction to Data Warehouse Interview Questions

Top 15 Data Warehouse Interview Questions and Answers

Below are the top question and answers of the data warehouse as follows. These questions are helpful while giving mock tests or interviews.

Q1. What is a dimensional table in the data warehouse?

Answer:

This table includes the textual attributes for measurement saved in a fact table. The dimensional table is nothing but the group of hierarchy and logic which is used for the customer to traverse the specified node. A dimensional table is very important while working with the data warehouse.

Q2. What is a data warehouse?

Answer:

A data warehouse is data accumulated huge storage for a broad range of sources used to guide the business. The data warehouse contains the central repository information used to analyze to make good business decisions. Data flow into the data warehouse from the relational databases, typically regular cadence. The decision maker accesses the data by using SQL clients and BI tools. Data and analytics are both indispensable to each other.

Q3. What different methods are used in the data warehouse for loading the dimension tables?

Answer:

We are using direct and conventional methods for loading the dimensional table in the data warehouse. All the keys and constraints are validated against the information before we load it. All the keys and constraints are disabled before loading the information. We can validate the same using keys and constraints.

Q4. What is a fact table in a data warehouse?

Answer:

This table includes the measurement of the business process. This table includes the foreign key of dimension tables. Example – If we are in the business phase in the paper, the normal production of one device or weekly production is treated as a business process measurement.

Q5. What is data mining in the data warehouse?

Answer:

Data mining is the phase for analyzing data from multiple perspectives and summarizing the same data. Data mining is the process of sorting data from large datasets to identify the relationships and patterns that can help solve business problems. Data mining tools enable enterprises to predict business trends. It contains the key parts of data analysis.

Q6. What is OLAP in the data warehouse?

Answer:

OLAP is nothing but the analytical processing of data online. This system does not contain real-time data. OLAP performs multi-dimensional analysis at high speed and large volumes of data from a data mart or data warehouse. Multiple business data contain multiple categories and dimensions. OLAP is useful, but our data does not contain real-time information.

Q7. What is OLTP in the data warehouse?

Answer:

OLTP is nothing but the transaction processing data online. This system contains real-time data. This is the type of transaction processing that includes the number of transactions occurring concurrently. Those transactions are referred to as financial transactions. This type of application is used in banking or shopping website. In an OLTP transaction, data is stored real-time in a database.

Q8. What is ODS in data science?

Answer:

ODS is nothing but the operational data store. ODS shares and allows the operational database information. The ODS is becoming the shared enterprise operational database, which allows the operational function that is re-engineered for using the ODS in their operational database.

Q9. What is the use of ETL in the data warehouse?

Answer:

ETL is the software that allows businesses to develop disparate records while moving them from one place to another. The ETL data is coming from multiple sources. ETL manages those types of data very efficiently. The function reads the data from the particular source database and extracts the desired subset of the data. The transform function works with the record by using rules for creating a combination with other records to convert the same into the desired state.

Q10. What is real-time data warehousing?

Answer:

Real-time data warehousing means it will capture the event of business when it will happen. A data warehouse captures the event data of a business. When the business event is complete, the completed event data flows into the data warehouse, and it will become instantly feasible.

Q11. What are conformed dimensions in the data warehouse?

Answer:

Conformed dimension in the data warehouse will define the same thing as the fact table when it was joined. A conformed dimension is a very important term in a data warehouse. We are using the same while defining the table conditions.

Q12. What is star schema in the data warehouse?

Answer:

Star schema in a data warehouse is the type of table from which we are fetching the result instantly.

Q13. What is the snowflake schema in the data warehouse?

Answer:

Extended dimension by using any dimension is called a snowflake schema in a data warehouse. The dimension is interlinked with one or multiple tables’ relationship with the other tables. The snowflake schema is normalized, and the outcome will come in complex joins, and it will contain complex queries and slower results.

Q14. What is active data warehousing?

Answer:

Active data warehousing provides the data that allows a decision-maker to handle the customer relationship. An active data warehouse is a combination of features, products, and services which supports the business strategy. In active data warehousing, the transactional data captures and reposts into the active data warehouse. This repository utilizes the patterns and finding trends used for decision-making.

Q15. What is a bus schema in the data warehouse?

Answer:

In the data warehouse, bus schema is collected from the master suite, and it will contain the facts of standardized description. Bus schema is used for identifying the dimensions across the process of business. This schema defines the facts and conformed dimensions across the data marts.

Conclusion

In this article, we have explained the top questions and answers to the data warehouse framework. These questions and answers are very useful at the time of giving the interview and attending any test related to big data or ETL.