11 Questions to Ask in an Interview About Normalization (With Sample Answers)
Normalization is an important part of what IT, database, and software development workers do. A hiring manager may ask you a series of questions about your skills, knowledge, and qualifications during an interview. Preparing for common questions about normalisation and how it works can help you answer them more clearly in your interview, which can increase your chances of getting hired. In this article, we look at a list of 11 interview questions about normalisation and give examples of how to answer them.
Interview questions and answers about normalisation as examples
Think about these 11 questions and answers about normalisation as you prepare for your next interview:
1. What is normalisation, and how is it different from denormalization?
This could be the easiest question an employer asks, and it helps them figure out how much you know about the subject. Try to give a short explanation of what “normalisation” means in your answer, and then move on to what “denormalization” means. Try to make sure your answer shows how they are different.
Normalization is the process of setting up a database’s columns, rows, and tables so that data doesn’t get repeated too much. It is often used in systems for online transaction processing, or OLTP, to break up large tables into smaller ones that show how they are related. Denormalization, on the other hand, makes data work better by grouping data together and adding data that is already there. It is used in systems called “online transactional processing,” or “OLAP.”
2. What are the different forms or levels of normalisation?
You can name a lot of different normalisation levels, but sometimes it’s best to give a short answer because hiring managers often have a lot of candidates to talk to and limited time. In your answer, try to name the first three levels of normalisation. You can say more about some things you didn’t mention if you have time or if the manager asks.
“I’m most familiar with the first three normalisation forms. The first is about getting rid of groups that are repeated, and the second is about getting rid of data that is already there. In the third form of normalisation, columns that don’t depend on a key are removed. I’m also familiar with the Boyce-Codd form, the optimal form, and the domain-key form.”
What are keys in normalisation?
Normalization depends on keys, so the employer will probably ask you about them at the interview. There are a lot of keys you could name, but if you don’t have time or can’t remember them all, you might want to name at least three or four. You can tell me more about what those keys mean if you can.
He said, “There are three main keys to getting things back to normal.” The primary key, the foreign key, and the unique key are the three types. The primary key is used to make sure that each row in a table is unique and to stop values that are null or don’t exist from being used. The foreign key is used for columns where the values depend on the values of the primary key in other tables. The unique key identifies ev
4. What is a join, and what are the different types of joins?
Joins are a common part of normalisation and SQL queries, so if an employer asks you about them, it’s probably to see how well you know them. Try to say what it is in a few words, and then list the kinds. Try to think of at least three of them if you can’t think of all of them to show that you know something about them.
“A join is a tool in SQL queries that pulls data from more than one table and puts it all together.” I’m not sure, but I think there are five joins. There are inner, left, right, self, and full joins. They pull records from tables based on where they are and what values match.
5. Why is standardising a good idea?
If an employer asks you this, they probably want to know how you’ve used normalisation in the past and how well you understand what it’s for. Try to tell them at least two or three good things about normalisation to show that you know what you’re talking about. You might want to keep each benefit short so that you can list more and show off your work experience.
“There are many benefits to using normalisation, but in my experience, there are three main ones. First of all, normalisation works well to get rid of existing records and entries. By doing this, valuable database storage space is saved, which is another big benefit. Last but not least, I think normalisation makes queries run faster and easier to manage.
6. What does the acronym ACID stand for, and what are its properties?
ACID is a concept that has to do with databases, so it’s important that you understand what this means. In your answer, try to tell what ACID stands for and then list each part of the acronym. You could say more about what each one means if you have time or if the employer asks you to. This would show how knowledgeable you are.
“ACID stands for the core transaction properties, and it has four properties. There are four of them: atomic, consistent, isolating, and lasting. Atomic means that each transaction either works or it doesn’t. Consistent means keeping a database that is always the same and getting rid of incomplete transactions. Isolation means that only the user can see the changes they make until the transaction is finished. When a deal is durable, it means that it can’t be broken.
7.What is a SQL statement, and what kinds are there?
Normalization is a big part of SQL, so employers often ask about it in some way. This is a simple question, so try to explain what a SQL statement is and list the different kinds of SQL statements. You can also give more information about each kind.
“An SQL statement is a type of code that lets you get information from a database. I know about four SQL statements, which are the data definition language, the language for manipulating data, the language for controlling data, and the language for controlling transactions. “Data definition” refers to the structure that holds the data. You can get information from the database, change it, add to it, or take it out. In a database system with more than one user, data control decides who can see what and how it is kept safe. You use transaction control to keep track of any changes your data manipulation statements make to your database. It also lets you group these statements into logical transactions.
8. What do union and union all mean? How are they different?
This is a comparison question that helps employers see if you can tell the difference between ideas that seem similar. Try to make the difference between the two ideas clear so the employer is less likely to misunderstand or misread what you said. To help people see the difference, you can give more details than usual.
Example: “Union and union all are tools that merge the rows from multiple tables. However, union tries to remove any duplicate data records, while union all doesn’t. Union also sorts data and records in ascending order, but union all does not. Comparatively, union all is much faster than union.”
What’s the difference between a relationship with one person, a relationship with many people, and a relationship with many people?
This is another comparison question where an employer wants to see how well you understand similar ideas and how they are different. This question asks about three things, so try to answer all of them.
Example: “A one-to-one relationship is a link that only exists between two data points. For example, each name in a database is linked to a single phone number that is only used for that name. A “one-to-many” relationship is when a name links to more than one piece of information, like a phone number, ID number, or address. When more than one name links to more than one piece of data, this is called a “many-to-many” relationship. One way this can happen is with names and food products. One name can mean more than one type of food, and one product can mean more than one person.
10. What are truncate and delete, and how are they different?
This is a common question to see how well you understand technical things. First, try to explain each term on its own. Then, talk more about how they are different. They both have to do with taking information out of a table, so make sure that’s clear in your answer.
“The “truncate” and “delete” commands are used to remove data from tables. But truncate is a language statement that defines data, while delete is a language statement that changes data. Also, truncate doesn’t make rollback segments, but delete does. You can get back files you deleted with delete, but not with truncate.”
11. Explain the differences between an insert anomaly, an update anomaly, and a delete anomaly.
This is another question that asks you to compare and contrast three related ideas in a clear way to see how well you know and understand them. If you answer this question with confidence and clarity, the hiring manager might be able to figure out what tasks you could do if they hired you.
Example: “An insert anomaly happens when you can’t put data into some attributes because you don’t have other needed attributes. When one or more duplicated data rows are changed, but not all of the rows are changed at the same time, this is called a “update anomaly.” Because of this, the data is wrong. A delete anomaly is when some attributes disappear because other attributes disappear.
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