PHP: How to update a variable of a parent class from a child class

问题

I have a function in a child class which counts the number of SQL queries in a page load

In the child class which extends the parent class, after every: mysql_query($query);

I put parent::update_query_function();

where update_query_function() is:

function update_query_function(){

$this->query_num++;

}

the $query_num variable in the parent class is not being updated. Why?

回答1:

If your child class extends the parent class there's no need to do that, do this instead:

$this->update_query_function();

that's the point of inheritance.

来源：https://stackoverflow.com/questions/3786620/php-how-to-update-a-variable-of-a-parent-class-from-a-child-class