Method: Prepares the ORDER BY sql statement. It uses `$this->sort_by` to know which columns are sortable. This requests validates the orderby $_GET parameter is a valid column and sortable. It will also use order (ASC|DESC) using DESC by default.

Method: Return the sortable column specified for this request to order the results by, if any.

Method: Return the sortable column order specified for this request.

Method: Return the status filter for this request, if any.

Method: Return the search filter for this request, if any.

Method: Process and return the columns name. This is meant for using with SQL, this means it always includes the primary key.

Method: Check if the current request is doing a “full text” search. If that is the case prepares the SQL to search texts using LIKE.

Method: Prepares the SQL to filter rows by the options defined at `$this->filter_by`. Before trusting any data sent by the user it validates that it is a valid option.

Method: Checks if the current request has a bulk action. If that is the case it will validate and will execute the bulk method handler. Regardless if the action is valid or not it will redirect to the previous page removing the current arguments that makes this request a bulk action.

Method: Prepares the data to feed WP_Table_List.