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In technical interviews, interviewers usually ask about some professional programming knowledge to evaluate the applicant's technical understanding, logical thinking, and problem-solving methods. These questions are not only an examination of knowledge points, but also a way to understand the depth of the candidate's thinking by exploring technical concepts. Below I will give a detailed introduction to the common interview questions such as UI/UX, MVC, SQL, and API to help applicants better understand and deal with these technical topics.

1. What is UI/UX?​

UI and UX are two concepts that are often mentioned in the field of design, especially in software and web design. The importance of UI and UX is self-evident. Although these two terms often appear together, they refer to different things.

UI (User Interface) - User Interface

UI is the user interface, which refers to the visual and interactive part of the user's interaction with the system. The main purpose of UI design is to optimize the user's visual experience on the application or website, which includes layout, buttons, fonts, colors, icons and other elements that users can see. A good UI design should not only be beautiful, but also easy to operate, helping users achieve their operational goals faster and more effectively.

Factors to consider in UI design include:

  • Consistency: The style and color of UI elements should be consistent, so that users can understand and adapt to the interface more easily.

  • Visual appeal: Through the combination of color, typography and graphics, the interface is more beautiful and makes users feel happy during use.

  • Operability: The design of each button, icon or link should be simple and easy to understand so that users can intuitively know how to operate it.

UX (User Experience) - User Experience

UX is user experience, which focuses on the overall experience that users get when using a product. The core of UX design is to optimize the usability and practicality of a product by understanding the needs and pain points of users. UX involves every step and every process of user use, not just the visual interface. It includes every interaction between the user and the product, including functions, speed, navigation, readability of information, etc.

UX design usually answers the following questions:

  • Do users feel convenient during use?

  • Does the product meet the user's expectations?

  • Will the user encounter confusion during the operation?

  • Can the product bring a pleasant experience to the user during use?

2. What is MVC?​

MVC is a common software design pattern, especially suitable for developing user interface-based applications. MVC is the abbreviation of Model-View-Controller. It divides the application into three core parts: Model, View, and Controller. This layered design can make the development process clearer and the division of responsibilities clearer.

Model

Model is the core data logic layer of the application, responsible for processing data and business logic. It can get data from the database and update the database when needed. For example, in an e-commerce application, user information, order data, product inventory, etc. are all stored in the Model.

View

View is the user interface layer, responsible for displaying information and receiving user input. It is a bridge between the user and the application. View displays the data in the Model and triggers the Controller to update the Model based on the user's operation. For example, tables, text boxes, buttons, etc. on a web page belong to View.

Controller

Controller is the middle layer, responsible for processing user input, converting the input into Model operations, and deciding which View to use to display the Model data. It can be considered as a bridge between Model and View, responsible for coordinating the communication between the two. For example, when a user clicks a button, the Controller calls the corresponding Model operation and then updates the View.

The MVC design pattern can make the code structure clearer, improve the readability and maintainability of the code, and also support code reuse, facilitating team collaborative development.

3. What is SQL?​

SQL (Structured Query Language) is a structured query language and a standard language for relational databases. SQL is used to manage and manipulate data in a database and is an essential tool for database developers and managers.

In SQL, there are several common operations:

Data query (SELECT)

The SELECT statement is used to retrieve data from a database. It can select specific columns, rows, or perform aggregate operations. For example:

SELECT name, age FROM employees WHERE age > 30;

The above statement retrieves the name and age of employees older than 30 from the employees table.

Data insertion (INSERT)

The INSERT statement is used to insert new data into a table in a database. For example:

INSERT INTO employees (name, age, department) VALUES ('Alice', 28, 'Sales');

Data update (UPDATE)

The UPDATE statement is used to update existing data in a database. For example:

UPDATE employees SET age = 29 WHERE name = 'Alice';

Data deletion (DELETE)

The DELETE statement is used to delete data in the database. For example:

DELETE FROM employees WHERE name = 'Alice';

SQL can help developers add, delete, query and modify data in the database through these basic operations. SQL is a declarative language. Users only need to tell the system "what to do" without worrying about "how to do it", which makes SQL very easy to learn and use.

4. What is API?​

API (Application Programming Interface) is an application programming interface, which is a bridge between applications, allowing them to communicate with each other and transfer data. In modern software development, API is widely used, especially in distributed systems and microservice architectures, where API has become an important link for interaction between systems.

API Types

APIs can be divided into many types, such as:

  • Web API: used for communication between Web services, usually based on the HTTP protocol. Common Web APIs include RESTful API and GraphQL.

  • Library API: used for communication between libraries and applications, such as the APIs provided by standard libraries of languages ​​such as Java and C++.

  • Operating System API: used for communication between operating systems and applications, such as the Win32 API of Windows.

RESTful API

RESTful API is a Web API design method based on the REST (Representational State Transfer) architecture, which follows the principles of resource access and operation. Generally, RESTful API uses HTTP methods to perform CRUD operations:

  • GET: Get resources from the server.

  • POST: Create a new resource to the server.

  • PUT: Update resources on the server.

  • DELETE: Delete a resource from the server.

For example, suppose an e-commerce application API provides a /products interface, then:

  • Send a GET /products request to get information about all products.
  • Send a POST /products request to add a new product.
  • Send a PUT /products/{id} request to update the information of a product.
  • Send a DELETE /products/{id} request to delete a product.

The main function of the API is to achieve data sharing and function calls between different applications or services, thereby forming a collaborative ecosystem.

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