Do child classes inherit parent constants and if so how do I access them?

✔ Recommended Answer

I think you would need to access it like this:


or alternatively "parent", which will always be the value established in the parent class (i.e., the constant's immutability is maintained):


In both parent and children classes, you can use:



One thing that is interesting to note is that you can actually override the const value in your child class.

class MyParentClass{    const CONSTANT_1=1;}class MyChildClass extends MyParentClass{    const CONSTANT_1=2;}echo MyParentClass::CONSTANT_1; // outputs 1echo MyChildClass::CONSTANT_1; // outputs 2


Answered By: Chris Leyva

Method #2

Yes, child classes do inherit constants from their parent classes in PHP.

To access a constant defined in the parent class, you can use the parent:: keyword followed by the constant name. Here's an example:

class ParentClass { const PARENT_CONST = 'Parent Constant Value'; } class ChildClass extends ParentClass { } echo ParentClass::PARENT_CONST . "\n"; // Outputs "Parent Constant Value" echo ChildClass::PARENT_CONST . "\n"; // Outputs "Parent Constant Value"

In this example, we define a ParentClass with a constant PARENT_CONST. We then define a ChildClass that extends the ParentClass. The ChildClass inherits the PARENT_CONST constant from the ParentClass.

We can access the PARENT_CONST constant in both the ParentClass and ChildClass using the :: operator. When accessing the constant in the ChildClass, we use the parent:: keyword followed by the constant name to refer to the parent class constant.

Note that constants are always accessed statically, even if you are accessing them from an object context.


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