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Back End Developer Interview

20 Questions and Answers by William Swansen
| William Swansen is an author, job search strategist and career advisor who assists individuals from all over the world.

Question 1 of 20

How can you prevent SQL Injection attacks?

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Back End Developer Interview Questions

  1. 1.

    How can you prevent SQL Injection attacks?

      If this question looks familiar, it is. Interviewers will often ask different versions of the same question throughout an interview. The reason for this is to calibrate your answers to questions and make sure you are consistent. The best way to ensure that your answers to questions are the same is to answer them honestly and accurately. That way, you do not need to recall your previous answer to a similar question.

      William's Answer

      "There are several ways you can prevent an SQL injection attack. One way is closely defining the parameters for queries. This identifies nonstandard queries, allowing systems administrators to block them. A similar one uses prepared statements for queries and defines the SQL code they use. Another way to prevent SQL injection attacks is using stored procedures, in which a database administrator calls a procedure when they need it. The final methodology I prefer is known as lists input validation. This blocks any input which has not been stored on what is known as a white input list."

  2. 2.

    Can you describe a NoSQL database and how it differs from a relational database?

      Technical questions are defined as questions that ask you to discuss a term, process, or other aspects used in the work you perform. Technical questions will often ask you to compare one concept to another one. When answering this type of question, first define the term or concept, and then make the comparison. Keep your answer direct and to the point, and anticipate a follow-up question which the interviewer will ask to explore the topic in more detail.

      William's Answer

      "A NoSQL database is a mechanism that allows for the storage and retrieval of data and information. It is similar to a relational database, except a NoSQL database does not depend on tabular relations. A NoSQL database's common elements include key values, graphs, and both column and document orientation."

  3. 3.

    What Is CAP Theorem? How do you use it in your work?

      This is an example of a technical question. Technical questions will ask you about concepts, processes, or elements used in your work as a back end developer. The appropriate way to respond to a technical question is first defining the term and then describing how it is used. When answering technical questions, keep your answer brief and to the point, and anticipate a follow-up question.

      William's Answer

      "The CAP Theorem was developed by Eric Brewer. It states that a distributed computer system cannot provide Consistency, Availability, and Partition tolerances at the same time. The programmer's role is to determine which of these three qualities are the most important for the program they are creating. Then, they optimize one or two of the three to match the program's requirements. The CAP Theorem is used by major computer service providers to optimize the services they provide to users."

  4. 4.

    What is Containerization? What advantages does it offer over virtualization?

      This is an example of a technical question. Technical questions ask you to define the topic, concept, process, or work term used in your profession. They may also ask you to define the advantages of the concept or compare one concept to another. When answering technical questions, you should keep your response brief and to the point. The interviewer will ask you a follow-up question if they need additional information or want to explore the topic in more detail.

      William's Answer

      "Containerisation is a virtualization strategy that developers use to replace hypervisor-based virtualization. When using containerization, the OS is shared by each container. This is more efficient than cloning the OS for each virtual machine. It also makes them easier to manage by the systems administrators."

  5. 5.

    What does the acronym REST stand for?

      This technical question simply asks you to define a concept used in this profession. It is important to carefully listen to the questions you are being asked during an interview. This will ensure that you understand the question and provide the answer the interviewer is looking for. You should also wait until the interviewer finishes asking the question before thinking about your answer. This will ensure that your answer is the right one for the question. This was one of the most common mistakes candidates make during an interview.

      William's Answer

      "The acronym REST stands for REpresentational State Transfer. It is a web architecture that uses HTTP Protocol for data communication. The main principle behind REST is that every component is a resource which is accessed by the user interface using HTTP standards."

  6. 6.

    Can you discuss the main elements of a web API?

      You know the technical question. When interviewing for a back end developer's role, most of the questions you will be asked will be technical. These questions allow the interviewer to confirm your skills and experience while determining if these match the requirements of the role they are interviewing for. The best way to prepare for an interview is to study the processes you use daily and the technical terminology associated with them. This will keep the information fresh in your mind. You should also practice answering questions like these.

      William's Answer

      "There are several critical elements when defining a web API. These include statements communication, XML and JSON formatting languages, HPPT for communication between the client and the server, and simple URI for services."

  7. 7.

    Can you discuss the difference between a WHERE clause and a HAVING clause?

      This technical question asks you to compare two techniques utilized when developing a new software application. This is a typical example of a technical question. When responding to this type of question, first define each term and then compare them. In some cases, you may want to state the advantages one offers over the other, or provide an example of how they are used to strengthen your answer.

      William's Answer

      "The difference between a WHERE clause and a HAVING clause is based on whether the program uses aggregated columns. A WHERE clause can only be used when there are no aggregated columns, and the program uses static non-aggregated columns. By default, the HAVING clause is used on aggregated columns."

  8. 8.

    Which do you prefer, acceptance testing or functional testing?

      When asked a question about which process you prefer, it is best to answer by picking the one you use and then describing why you prefer it. Your rationale should discuss the benefits of the process, the technology it employs, and the operational advantages realized from using it. If you have done your research, you also can choose the process currently used by the employer to confirm that you will fit into their operations seamlessly.

      William's Answer

      "When given the option, I prefer functional testing to verify my code. This is because a functional test confirms that the product we developed works and performs the tasks we redesigned it for. The alternative is acceptance testing. This validates that we developed the product that the end-user requested and needs. It typically addresses whether the software solves the problem for the end-user. When using functional testing, it is important to clearly understand the end-users issue and the type of software they need to address it. Doing this enables the functional test to simultaneously perform the acceptance test."

  9. 9.

    Can you describe the software lifecycle methodology used in your current position?

      An interviewer will ask this question to determine if your current practices align with those used by their organization. When preparing for an interview, you should research the company to determine the programming languages and development practices they use. This will help you prepare to answer these questions. You could either confirm that you're using similar languages and methodologies or state that you use different ones. If you choose the latter option, make sure you can justify your answer and provide evidence as to why your methodologies may benefit the organization.

      William's Answer

      "Currently, my organization uses the Agile methodology for software development. The benefit of this is that issues are identified and addressed in real time before impacting our team's work later in the software development lifecycle. It also allows for iterative improvements in the processes, which results in more efficient practices later in the project."

  10. 10.

    What is the largest software project you have ever worked on? What was your role in the project?

      The purpose of this question is to determine the scope of responsibility you had on previous projects and the capabilities you will bring to this position. The interviewer assumes that larger projects are more complex and require greater skills, including organization, collaboration, and attention to detail. By understanding this, you can answer that question to address these concerns. Again, try to provide an answer the aligns with the type of software development work the organization currently does.

      William's Answer

      "The largest software development project I have worked on was creating a database of automotive parts for a car manufacturing company. The challenge was to inventory each part used by the manufacturer and cross-reference them with the vehicles they could be used on since many parts could be applied to multiple vehicles. My role was to create the SQL worries, so the workers could find the correct part by using common terminology they were familiar with."

  11. 11.

    Have you ever experienced a problem or encountered issues when using Object-Oriented Programming (OOP?)

      Questions like this can either stand on their own or be a follow-up to a previous question. During an interview, the interviewer will ask follow-up questions once you provide an answer. The reason for this is to explore a topic in more detail or confirm your knowledge of the topic. You should always be prepared for follow-up questions. Keeping your answers brief and to the point will encourage interviewers to ask follow-up questions and allow you to demonstrate your knowledge of the topic in more detail.

      William's Answer

      "While it is rare, I do occasionally encounter issues when using one of the object-oriented programming languages. These typically are due to a library or set of code I need not being available or having to rewrite the code for the object I need for my program. These issues are easily overcome. By adding my new code for the library, the issue is not likely to be encountered twice."

  12. 12.

    Can you describe the programming methodology known as Continuous Integration?

      This technical question asks you to define a process used in your profession. As a back end developer, you can anticipate that most of the questions you will be asked will be technical or operational. The best way to prepare for these is to review the terminology, processes, and other aspects of your job before the interview. Also, research the company you are interviewing with to determine the practices they use to create the products they develop. This will help you align your answer to their current processes.

      William's Answer

      "Continuous Integration, or CI, is a development methodology in which developers collaborate by adding their code to a central repository. Every time a developer does this, the entire code goes through an automated build, and the tools identify any errors or bugs which need to be addressed. This methodology is very similar to Agile programming."

  13. 13.

    Are you familiar with Go? What advantages does it offer a programmer?

      When asking this question, the interviewer is testing your knowledge of a specific technology that is likely in use within their operation. If the technology is a common one for your profession, you should know about it and be able to describe its function and advantages. If it is obscure or rarely used, it is OK to acknowledge that you don't know about it, and then describe how you would go about learning it.

      William's Answer

      "Go is a relatively new language being introduced to the programming profession. The benefits the developers of GO claim are its unstructured nature, fast compilation, and low overhead. The main use of Go is to collect garbage within the code. It was specifically developed to create system software on multicore computing devices."

  14. 14.

    What advantages does MongoDB have over common SQL databases, such as Oracle?

      Many questions you will be asked during an interview will ask you to compare two or more items. Interviewers will use these types of questions for several reasons. First, they help to confirm your knowledge of the topics. Second, it enables them to understand your preferences. And finally, they can determine whether you are familiar with the processes or technology used by their organization. Reviewing the terms, concepts, and processes used in your job and researching the company to understand what technologies the employer utilizes will help you be prepared to respond to these types of questions.

      William's Answer

      "Most SQL databases use very formal structures including tables, rows, columns and records to store and retrieve data. While this is easy to organize and manage, it is not very flexible. On the other hand, MongoDB uses a flexible structure that allows it to be modified and extended, based on the requirements of the data and the queries used by the program."

  15. 15.

    Can you provide some reasons why you would utilize a microservices architecture?

      This technical question assumes that you are familiar with Microservices Architecture. When preparing for an interview, you should research the organization to determine its technologies and programming methodologies. Knowing this will help you prepare for questions like these. If you're not familiar with the topic the interviewer is asking you about, it is okay to admit this, as long as you state how you would go about acquiring the knowledge or the skills needed.

      William's Answer

      "There are several reasons you would employ a microservices architecture when developing software. The first is that microservices are flexible and easily adapt to multiple frameworks and technologies. Another reason is that when one process fails within a microservices environment, the others are not affected. Microservices are also applicable across all sizes of organizations, and they can be deployed quickly when needed."

  16. 16.

    What advantages do web services provide over hosted applications?

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  17. 17.

    Can you describe some steps used in performance testing?

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  18. 18.

    What programming languages do you prefer to work with and why?

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  19. 19.

    Can you describe an SQL injection attack? What measures can be taken to prevent it?

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  20. 20.

    What experience do you have working with object-oriented programming (OOP) languages?

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