PHP

How is the guaranteed creation of only one instance of the Singleton class implemented?

Can you list the key advantages and features of abstract classes in object-oriented programming?

What consequences may arise if a transaction is not completed successfully and is rolled back?

Can you name the main access modifiers and their features?

Can you list the main design patterns for classes?

What steps should be taken when using abstract classes in object-oriented programming?

Explain what abstract classes are in object-oriented programming.

What is the main function and purpose of the PDO extension when working with databases in PHP?

In what situations is it advisable to use the Singleton pattern?

Which OOP principle is considered the most fundamental for building reliable objects?

How is information exchanged between tables in a relational database?

What methods of implementing and using abstract classes are you familiar with?

What is your experience developing in pure PHP without using third-party frameworks?

Can you list the main types of HTTP requests used in web development?

Show an example of using a nested SQL query.