31 Interview Questions About Database Design (With Sample Answers)
The way many businesses work depends on how well they collect and analyze data. Because of this, companies often look for people who know how to make databases and keep data management systems running. If you want to work in database management or administration, knowing what kinds of questions you might be asked can help. This article looks at 31 of the most common database design interview questions and gives you sample answers to help you think of your own.
25 general database design interview questions
Here are 25 more interview questions about database design that you might be asked:
- How do you put together a database?
- How would you describe a well-known model?
- How does the CAP theorem work? What is it?
- Explain the difference between an AP database and a CP database.
- What is horizontal scaling? What are its pros and cons?
- How does scaling up or down work? What advantages and disadvantages does it provide?
- What is a relational database, and why would you want to use one?
- How would you describe a database that doesn’t use relationships?
- What are some kinds of databases that don’t use relationships?
- Give some examples of different types of database keys.
- Tell me about the work you’ve done with databases before.
- How do you describe a schema?
- What are some of the most common schemas used by people who make databases?
- Which five types of dimensions are the most common?
- Explain the differences between DBMS and RDBMS.
- In terms of designing a database, explain what normalization and denormalization mean.
- What do you think of when you hear the words “scalar” and “aggregate”?
- What does it stand for?
- How are OLAP and OTLP different from each other?
- What is collation sensitivity, and what are the different types?
- Explain what a “table” and a “field” are when it comes to collecting and storing data.
- Show how you could save your data in case you lose it.
- What do you know about DBMS?
- How is a clustered index different from a non-clustered index?
- What does it mean to “query” and “subquery”?
6 database design interview questions
Here are six questions and answers about database design to help you get ready for your next interview:
1. What is database design and what role does it play in business?
This is a general question that interviewers may ask at the start of the conversation. This question is often asked to see how well you understand basic database design concepts and how you approach work. This question can also help the interviewer figure out how your way of making databases can help the company as a whole.
Most of the time, it’s best to avoid specifics when answering this question and instead talk about the role of data and databases in business today. You can say briefly why businesses collect data and why it’s important. Then you can talk about how databases and database designers help businesses get more out of the information they gather.
“Database design is the way that professionals like me make a detailed data model of a database.” This means making choices about both the physical and logical design, like setting the physical storage parameters needed to make a design in a data definition language. I can then use this information to make a new database.
During this process, I think about things like the availability of the data, the replication of the data, the partitioning of the database, the backup of the data, and the security of the system. In business, the goal of this process is to find the connections between the different entities in the data and normalize the data so that a company can understand, manage, and analyze the patterns in its data.
2. What are the main steps to making a database in general?
Most database design is done in three steps, and people who work in the field need to know what these steps are. This is a broad question that can help the interviewer see how well you understand important database design ideas. It can also show them how you might make a database for the company if they hire you.
When answering this question, it’s usually best to keep your answer short and show how well you know the subject. This can show potential employers that you’re ready to move on to more difficult subjects. You can start by talking about the three main steps in making a database. Then you can talk about why it’s important to take these steps.
Here’s what I mean: “In general, making a database is done in three steps. The first step is the conceptual database design, where we make an idea of how the data system will work. This means figuring out what the entities in the data ecosystem are, how they relate to each other, and what their attributes are. The second step is to make sense of the database. At this point, we choose a data model and turn the conceptual model into a logical framework.
Making a physical database model is the last step in designing a database. At this point, we figure out how to make the logical model work in the real world. This means choosing a database management system, deciding on security measures, and coming up with ways to store and organize files.”
3. What is a logical model, and how do you make one?
Creating a logical database model is often the second step in making a database solution. It lets designers try out their ideas with a certain data model before making a database that fits a company’s needs. Hiring managers might ask you this question to see how well you know how to do this important job.
When you answer this question, you can briefly explain what a logical model is. Then you can explain what part it plays in making a database. Lastly, you can make a short list of the steps you would take to make a logical model. This can help you show interviewers that you know how this process works in the real world.
Here’s an example: “A logical database model, also called a logical schema, is a data model that focuses on a specific problem domain and is not tied to a specific database storage technology or management product. This model sends information by using data structures like object-oriented classes, relational tables and columns, and XML tags.
In seven steps, I can make one. I set the goals for the database logical model design, then I look at the existing database, make a database structure, and set up the table relationships for the model. The last three steps are to set up the database model views and make sure that the schema I made is correct.
4. Give an explanation of what a conceptual database model is and how it looks.
Creating a conceptual model of the database is often the first step in designing a database. It gives a general idea of what is needed for a database to work. Conceptual database models are something that people who work in database design need to be able to understand. The interviewer can figure out how qualified you are in this area based on how you answer this question. When answering this question, you might want to start by briefly explaining what a conceptual database model is and what role it plays in the process of designing a database. The next step is to talk about some of the most important parts of a good conceptual model.
Here’s an example: “A conceptual database model is a description of a company’s database needs that I can use to design and build a database that takes its priorities and preferences into account. This model usually shows the main ideas that a business wants to focus on and how those ideas relate to each other.
The main purpose of this type of model is to give a data-driven overview of a company. It does this by keeping track of internal business events and looking at how different parts of an organization work together to support business processes. This model doesn’t try to figure out how a database is made or how it works. Instead, it just looks at the information that a group uses. The data types, names, and characteristics and qualities of business entities are the most important parts of a conceptual database model.
5. What is a physical database model, and how could you make one?
Most of the time, the last step in designing a database is to make a physical database model. These models show how the database is really set up and bring together the logical and conceptual parts of the design. Finishing a physical database model is one of the most important things for database designers to do. Interviewers might ask you this to see how much you know about the field. Your answer can also give them an idea of how well you might do on the job if they hire you.
You can start to answer this question by telling me what a physical database model is. Then you can talk about what role it plays in making a database. Lastly, you can give a brief summary of the steps you might take to make a physical database model. If you’ve done one before, you can show that you’ve done it before by giving details.
Here’s an example: “A physical database model is a database-specific tool that includes all the logical database elements that professionals need to build a database, such as a column name, column data type, primary key, foreign key, column constraints, and relationships between tables. This model shows how a data design was put into place or is hoped to be put into place by professionals in a database management system. It could come from a logical database model, but that depends on the project.
To make a physical database model, I follow a set of eight steps. I look for the tables and make sure they are all the same. Then I set up the columns and look at the stored procedures. Next, I use the organization’s standards and guidelines for naming conventions to figure out how the tables are related. Last, I use the data model patterns and make sure that the right keys are assigned.”
6. What is a physical database model, and what does it include?
Logical and conceptual database models are often different from physical database models in a number of ways. People who make databases need to know about these features so they can use them in their work. When they ask this question, interviewers usually want to see how well you understand and can use common database design ideas.
Most of the time, it’s best to give clear, short answers to this question. Try writing down four or five things about physical database models that are important. You could talk about why these traits are important and what role they play if you have time.
Here’s what I mean: “A physical database model is a plan for making a logical database model work in the real world. There are many ways in which physical models are different from logical models. First, they are unique to a DBMS, whereas logical models can be used with any DBMS. Physical database models also show the storage structures, access methods, security features, table structures, and table constraints. A database that works and is safe enough for professionals to use at work is made up of all of these parts.”