Help me to solve a little doubt, thank you

Help me out with a little problem, thank you.
Abstract class abs_db{//Abstraction classes
Abstract protected function connect ();//Database connection
Abstract protected function select_db ();//Select Database
Abstract protected function SetChar ();//Character Set
Abstract protected function query ();//Query
Abstract protected function getAll (); Remove part of a query
Abstract protected function GetOne ();//Remove one of the queries
Abstract protected function error ();
}
Class MySQL extends abs_db{
}

?>

The above code appears error prompt class ' MySQL ' must implement inherited abstract method
' Error (...) ' What is the reason for this and how to solve it? The compiler I'm using is the Zend Studio 9.0.3 version.

------Solution--------------------
That is, a subclass inherits a parent class, and the parent class is an abstract class, and you must implement the functions in the parent class within the subclass class.
For example:

PHP Code

Abstract class a{   Funca ();}
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