<?php
/**
 * Implements the Repository Pattern to deal with sum of Active Records
 *
 * @version    4.0
 * @package    database
 * @author     Pablo Dall'Oglio
 * @author     Marco Driemeyer <marco@plenatech.com.br>
 * @copyright  Copyright (c) 2006 Adianti Solutions Ltd. (http://www.adianti.com.br)
 * @license    http://www.adianti.com.br/framework-license
 */
class TRepositorySum 
{
    private $class; // Active Record class to be manipulated
    private $criteria; // buffered criteria to use with fluent interfaces
    
    
    /**
     * Class Constructor
     * @param $class = Active Record class name
     */
    public function __construct($class)
    {
        if (class_exists($class))
        {
            if (is_subclass_of($class, 'TRecord'))
            {
                $this->class = $class;
                $this->criteria = new TCriteria;
            }
            else
            {
                throw new Exception(AdiantiCoreTranslator::translate('The class ^1 was not accepted as argument. The class informed as parameter must be subclass of ^2.', $class, 'TRecord'));
            }
        }
        else
        {
            throw new Exception(AdiantiCoreTranslator::translate('The class ^1 was not found. Check the class name or the file name. They must match', $class));
        }
    }
    
    
    /**
     * Returns the name of database entity
     * @return A String containing the name of the entity
     */
    protected function getEntity()
    {
        return constant($this->class.'::TABLENAME');
    }
    /**
     * Return the sum of columns of objects that satisfy a given criteria
     * @param $criteria  An TCriteria object, specifiyng the filters
     * @param $columns   An indexed array with the name and the column to sum
     * @return           An stdClass with the named property storing the sum of values
     */
    public function sum(TCriteria $criteria = NULL, array $columns)
    {
        if (!$criteria)
        {
            $criteria = isset($this->criteria) ? $this->criteria : new TCriteria;
        }
        // creates a SELECT statement
        $sql = new TSqlSelect;
        
        // Interact with the array and add the columns to sum
        foreach ($columns as $key => $column)
        {
            $sql->addColumn("sum ($column) as $key");
        }
        
        $sql->setEntity($this->getEntity());
        // assign the criteria to the SELECT statement
        $sql->setCriteria($criteria);
        
        // get the connection of the active transaction
        if ($conn = TTransaction::get())
        {
            // register the operation in the LOG file
            TTransaction::log($sql->getInstruction());
            
            $dbinfo = TTransaction::getDatabaseInfo(); // get dbinfo
            if (isset($dbinfo['prep']) AND $dbinfo['prep'] == '1') // prepared ON
            {
                $result = $conn-> prepare ( $sql->getInstruction( TRUE ) , array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
                $result-> execute ( $criteria->getPreparedVars() );
            }
            else
            {
                // executes the SELECT statement
                $result= $conn-> query($sql->getInstruction());
            }
            
            if ($result)
            {
                $row = $result->fetch();
             
                // Initiate the stdClass and interact with the return of the sum 
                $stdClass = new stdClass();
                foreach ($columns as $key => $column)
                {
                    if ($row["$key"])
                        $stdClass->$key = $row["$key"];
                    else
                        $stdClass->$key = 0;
                }
                
                return $stdClass;
            }
        }
        else
        {
            // if there's no active transaction opened
            throw new Exception(AdiantiCoreTranslator::translate('No active transactions') . ': ' . __METHOD__ .' '. $this->getEntity());
        }
    }
    
    public function get(TCriteria $criteria = NULL, $callObjectLoad = TRUE)
    {
        return $this->load($criteria, $callObjectLoad);
    }
}
?>
 

 
<?php
    $reposum = new TRepositorySum('ModelToSum');
    $criteria = new TCriteria();
    $criteria->add(new TFilter('column1', '>=', '1'));
    $criteria->add(new TFilter('column2', '=', '3'));
                        
    // TRepositorySum retorna a soma de uma ou mais colunas dentro de um objeto stdClass, as colunas a serem somadas são informadas no momento da chamada do metodo
    // Para somar, basta chamar o metodo sum com um array indexado no qual informamos o nome da propriedade que deve receber a soma no objeto que será retornado e os campos a serem somados
    // Realizamos testes em PostgreSQL e MySQL, mas possivelmente funcione em outros bancos, se não funcionar a lógica para implementar a soma nesses banco esta exposta e pode ser ajustada
    $simpleSum = $repo->sum($criteria, array('return_name' => 'column_to_sum'));
    echo "$simpleSum->return_name"; // retorna a soma da coluna column_to_sum realizada no banco de dados
    $otherSum = $repo->sum($criteria, array('return_name' => 'column_to_sum', 'return_sum' => 'column_to_sum_1 + solumn_to_sum_2'));
    echo "$otherSum->return_name"; // retorna a soma da coluna column_to_sum realizada no banco de dados
    echo "$otherSum->return_sum";   // retorna a soma das colunas column_to_sum_1 + column_to_sum_2 realizada no banco de dados
?>