PHP 7 Constants Notice: Constant already defined LESSON 13

Video For PHP Constants Lesson

If you’ve worked with PHP for any length of time, you may have come across the “Notice: Constant already defined” error message. This error can be confusing, especially if you’re not familiar with constants in PHP. In this blog post, we’ll take a closer look at what constants are, how to define them, and what causes the “Constant already defined” error.

What are constants in PHP?

In PHP, constants are variables that cannot be changed once they are defined. They are similar to variables, but they have a fixed value that remains the same throughout the script. Constants are typically used for values that should never change, such as mathematical constants like pi or values that are used throughout an application, like database connection details.