system/classes/Db_MySQL.php
protected function calculate()
    {
      // Determine Action
      $action = false;
      $actions = 0;
      if($this->delete) {
        $actions += 1;
        $action = 'DELETE';
      }
      if(!empty($this->inserts)) {
        $actions += 1;
        $action = 'INSERT';
      }
      if(!empty($this->updates)) {
        $actions += 1;
        $action = 'UPDATE';
      }
      if(!empty($this->selects)) {
        $actions += 1;
        $action = 'SELECT';
      }
      if(!empty($this->create)) {
        $actions += 1;
        $action = 'CREATE';
      }
      if ($actions > 1) {
        throw new \Exception("More than one query action specified! When using Cora's query builder class, only one type of query (select, update, delete, insert) can be done at a time.");
      }
      else {
          $calcMethod = 'calculate'.$action;
          $this->$calcMethod();
      }      
    }
protected function calculate()
    {
      // Determine Action
      $action = false;
      $actions = 0;
      if($this->delete) {
        $actions += 1;
        $action = 'DELETE';
      }
      if(!empty($this->inserts)) {
        $actions += 1;
        $action = 'INSERT';
      }
      if(!empty($this->updates)) {
        $actions += 1;
        $action = 'UPDATE';
      }
      if(!empty($this->selects)) {
        $actions += 1;
        $action = 'SELECT';
      }
      if(!empty($this->create)) {
        $actions += 1;
        $action = 'CREATE';
      }
      if ($actions > 1) {
        throw new \Exception("More than one query action specified! When using Cora's query builder class, only one type of query (select, update, delete, insert) can be done at a time.");
      }
      else {
          $calcMethod = 'calculate'.$action;
          $this->$calcMethod();
      }      
    }
Create the SQL string from Database class raw data.