CodeIgniter Interview Questions

Updated March 4, 2023

Introduction to CodeIgniter Interview Questions and Answers

CodeIgniter is basically an open-source software development web framework, and it is mainly associated with PHP has driven website development works. It consists of a rich set of functionalities, and these are very useful for speeding up the website development works. It also follows the basic principles of MVC architecture.

If you are looking for a job related to CodeIgniter, you need to prepare for the 2023 CodeIgniter Interview Questions. It is true that every interview is different as per the different job profiles. Here, we have prepared the important CodeIgniter Interview Questions and Answers, which will help you get success in your interview.

This 2023 CodeIgniter Interview Questions article will present the 10 most important and frequently used interview questions. These Top questions are divided into two parts are as follows:

Part 1 – CodeIgniter Interview Questions (Basic)

This first part covers basic Interview Questions and Answers.

Q1. Explain the CodeIgniter supported databases?

Answer:
Find below the databases that are supported by the CodeIgniter framework:

1. Oracle: It has been supported with the help of PDO and oci8 drivers.
2. MySQL: It has been supported with the help of PDO and MYSQLI drivers.
3. ODBC: It has been supported via PDO and ODBC drivers.
4. SQLite: It is supported by SQLite2, SQLite3, and PDO drivers.
5. CUBRID: It is supported by the Cuboid and PDO drivers.
6. Interbase: It has been supported via iBase and PDO drivers.

Q2. Explain the CodeIgniter hooks features?

Answer:
These are the basic CodeIgniter Interview Questions asked in an interview. The CodeIgniter’s Hooks feature is mainly implemented to update the framework’s inner core functionalities, and this is performed without any interventions to core files in the frameworks. Find below few different available hook points implemented in CodeIgniter.

1. Pre_controller: It is normally called prior to all the called or associated controllers
2. Pre_system: It is generally called during the system execution process.
3. Post_controller: It is called exactly after the completion of the controller execution.
4. Post_controller_construcor: It is called after the controller execution initiation but prior to any method calls processing.
5. Display_override: It is initiated to override the display method.
6. Post_system: This is called after the end of the system execution phase and after the final page, and associated data is processed to the web page.

Q3. Explain different functions used in CodeIgniter?

Answer:
Find below few important functions used in CodeIgniter.

1. is_https()
2. get_mimes()
3. html_escape(var)
4. config_item(key)
5. is_php(version)
6. is_cli()

Q4. Explain the importance of CLI in CodeIgniter?

Answer:
CLI is basically text-based command-line interphase that is used for the interaction purpose by executing a set of commands. Find below few important uses of CLI.

1. Cronjobs can be executed without using wget or curl.
2. It is used to incorporate CodeIgniter with the other programming languages.
3. It can be implemented to set platforms, permissions, run caches, and other interrelated tasks.

Q5. What do you mean by the inhibitor in CodeIgniter?

Answer:
Inhibitors are basically errored handling classes that are associated with CodeIgniter, and these are implemented using different PHP functions. Find below a few different PHP functions that are implemented for the same.

1. Set_error_handler
2. Set_exception_handler
3. Register_shutdown_function etc.

Part 2 – CodeIgniter Interview Questions (Advanced)

Let us now have a look at the advanced Interview Questions.

Q6. Explain the routing in CodeIgniter?

Answer:
Routing is mainly implemented to define the URLs according to the defined requirements. It can be defined in two ways. These are Wildcards and Regular Expressions.

1. Wildcards: It can also be classified into two ways.
   1. : any – This is used for the series that consists of only matched characters.
   2. : num – This is used for the series that consists of only matched numbers.
2. Regular Expressions: This is mainly implemented to redirect routes. In the case of CodeIgniter, own regular expressions can be created and implemented to run and execute the URLs.

Q7. What do you mean by CodeIgniter Library?

Answer:
The CodeIgniter provides a different set of libraries, and these are useful with the continuous improvements and support of the application and also its corresponding enhancements. This is mainly located in the system->library section. There are different types of methods that can be used to create a library.

1. The process to create a whole new library.
2. The process to replace the native library.
3. The process to extend the native library.

Q8. Explain different features implemented by CodeIgniter?

Answer:
There are different features implemented in the CodeIgniter framework, and those are used to implement the web solutions in a more convenient manner. Find below few important features of the same.

1. The framework used in this case does have a small footprint.
2. The solutions provided through this framework normally traverses through the different library files. This help produces easier and simpler solutions in case of different critical and complex scenarios.
3. It goes through different layers of security patches, and thus it is considered to be a much-secured framework from the developer perspective.
4. The different inbuilt and created library files provide much swift and convenient output and performances from the end-user perspective.

Q9. Explain the helper files in CodeIgniter?

Answer:
This is the most popular CodeIgniter Interview Questions asked in an interview. Helper files are generally used to help the implementation of different tasks through the CodeIgniter frameworks. These helper files are mainly consisting of a different function of specific categories. These files are used to perform those tasks without hampering other methods and functions. There are also no dependency that exists for the other functions. CodeIgniter doesn’t load any helper files by default, and to use this feature, helper files need to be loaded initially. After the successful loading, it becomes globally available and accessible through different controllers and views. These files are generally used to get stored in the system/helpers directory.

Q10. Explain the advantages of using the CodeIgniter framework?

Answer:
Find below few important advantages:

1. It goes through different layers of security patches, and thus it is considered to be a much-secured framework from the developer perspective.
2. It is fast, reliable and lightweight and thus becomes more capable from the end-user perspective.
3. It provides extensive support across different library files.
4. It provides extensive support across different database providers.
5. In the case of PHP development, CodeIgniter proves to be a better choice due to its smart affordability and use of different library and helper files.

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