Top Data Warehouse Interview Questions

Last updated on Feb 06, 2023
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Data Warehouse Interview Questions

The data warehouse is the most secure storage system of any information for the business or the organization. This data warehouse works as the library of the historical data that can be analyzed or retrieved as per the requirements of the business to perform decision making. In this Data Warehouse Interview Questions article, we have consolidated the list of all the common questions that most companies usually ask during their session of interviews. We highly recommend you go through every question twice before going to the Data warehouse job interview. You don’t need to go anywhere for finding the answers, we have listed them as well for your convenience.

Most Frequently Asked Data Warehouse Interview Questions

Here in this article, we will be listing frequently asked Data Warehouse Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q1. Why do we need a data warehouse instead of a database?

A data warehouse is designed to separate the analysis of bigger data and processes the query from the transactional processes that are focused on writing.
We opt data warehouse instead of a database because of the benefits listed below:

  • It enables historical insight.
  • Enhances the quality of Data
  • Boost the efficiency
  • Drives the revenue
  • It increases the speed of data analytics
  • It provides data security
  • It has very much higher query performance and insights
Q2. Which database is best for the data warehouses?

Relational database (RDBMS). This database allows you to store detailed, consolidated, and company-wide data. It is based out on the design of “Star schema” and it is established by the various data marts that are integrated through dimensions and confirmed facts.
However, the best database software for the data warehouses will depend on your requirements.

Q3. What is data modeling in the data warehouse?

It demonstrates one of the most common ways of planning the blueprints of the definite and summed up information of the data warehouse. The objective of data warehouse modeling is to foster a diagram portraying the reality, or if nothing else a piece of the reality, which the data warehouse is expected to help.

Q4. What is the difference between various types of data warehousing?
Enterprise Data Warehouse Operational Data Store Data Mart
It gives the controlled database for decision support throughout the enterprise. Under its scope, it has a broad enterprise which is unlikely a real enterprise Data warehouse. In this, data gets refreshed in rare real-time and it is being used for daily business activity. It is a sub-part of the data warehouse. It is designed for particular lines of business, hence support for a particular reason.
Q5. Would you like to tell us the difference between Data Warehousing and Data Mining?
Data Warehousing Data Mining
It is defined as a huge database that is designed to carry out analytical processes. It is defined as the process that determines the hidden relationships in patterns among different sets of data.
It is used to combine huge sets of data. It determines the useful meaning and insights from large sets of data.
It can easily store large quantities of data of any organization. It is used to identify the patterns, frauds, and relationships in an organization.
Data warehousing can be performed by engineers. Data mining is performed by businessmen with the help of engineers.
Q6. What is the difference between OLTP and OLAP?
OLTP stands for Online Transaction Processing. OLAP stands for Online Analytical Processing.
It has fundamental business tasks It has Multi-dimensional business tasks
It is used to normalize small database It is used to denormalize large database
It supports simple queries by users It supports complex queries by the system.
Q7. What are the steps to build the data warehouse?

To build the data warehouse, one needs to follow the below steps:

  • Gather all the business requirements.
  • Necessary sources should be identified.
  • Identify the facts.
  • Dimensions should be defined.
  • Attributes should be defined.
  • Redefine the attributes and dimensions, if they are required.
  • Organize the hierarchy of Attribute
  • Define relationships.
  • Assign unique identifiers.
Q8. What are the main differences between structured and unstructured data?
Basis Structured Data Unstructured Data
Analysis Quantitative Qualitative
Searching Easy using SQL-based approaches May require the use of special tools
Storage It requires more storage to accommodate defined data structures. In this, some forms require less storage; others have large file formats, requiring more storage.
Format It has a predefined format that uses alphanumeric characters. It has typically non-character-oriented digital representations.
Q9. What are the types of dimensional modeling in data warehouses?

In Data warehouses, there are three types of dimensional modeling:

  • Conceptual Modeling
  • Physical Modeling
  • Logical Modeling
Q10. What is bus architecture in the data warehouse?

In the data warehouse, bus architecture is made up of the set of tightly combined data marts that gets their potential from fact tables and conformed dimensions.

1. Conformed dimensions

it is defined and implemented only once so that it is meant to be the same thing wherever it is being used.

2. Fact Tables:

which are conformed includes the things that derive revenue, profit, standard costs, and standard price.

This is it! We came to the end of this blog on the Data Warehouse Interview Questions. We hope you found this one helpful and are now feeling more confident about your upcoming interviews. If you think we are missing out on something, do not hesitate to tell us. Do share your feedback in the comments section.
Let us learn together and make a brighter future for all of us!

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