Subversion-Projekte lars-tiefland.prado

<?php
/**
 * TDbDataReader class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2008 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @version $Id: TDbDataReader.php 2541 2008-10-21 15:05:13Z qiang.xue $
 * @package System.Data
 */

/**
 * TDbDataReader class.
 *
 * TDbDataReader represents a forward-only stream of rows from a query result set.
 *
 * To read the current row of data, call {@link read}. The method {@link readAll}
 * returns all the rows in a single array.
 *
 * One can also retrieve the rows of data in TDbDataReader by using foreach:
 * <code>
 * foreach($reader as $row)
 *     // $row represents a row of data
 * </code>
 * Since TDbDataReader is a forward-only stream, you can only traverse it once.
 *
 * It is possible to use a specific mode of data fetching by setting
 * {@link setFetchMode FetchMode}. See {@link http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php}
 * for more details.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TDbDataReader.php 2541 2008-10-21 15:05:13Z qiang.xue $
 * @package System.Data
 * @since 3.0
 */
class TDbDataReader extends TComponent implements Iterator
{
        private $_statement;
        private $_closed=false;
        private $_row;
        private $_index=-1;

        /**
         * Constructor.
         * @param TDbCommand the command generating the query result
         */
        public function __construct(TDbCommand $command)
        {
                $this->_statement=$command->getPdoStatement();
                $this->_statement->setFetchMode(PDO::FETCH_ASSOC);
        }

        /**
         * Binds a column to a PHP variable.
         * When rows of data are being fetched, the corresponding column value
         * will be set in the variable. Note, the fetch mode must include PDO::FETCH_BOUND.
         * @param mixed Number of the column (1-indexed) or name of the column
         * in the result set. If using the column name, be aware that the name
         * should match the case of the column, as returned by the driver.
         * @param mixed Name of the PHP variable to which the column will be bound.
         * @param int Data type of the parameter
         * @see http://www.php.net/manual/en/function.PDOStatement-bindColumn.php
         */
        public function bindColumn($column, &$value, $dataType=null)
        {
                if($dataType===null)
                        $this->_statement->bindColumn($column,$value);
                else
                        $this->_statement->bindColumn($column,$value,$dataType);
        }

        /**
         * @see http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php
         */
        public function setFetchMode($mode)
        {
                $params=func_get_args();
                call_user_func_array(array($this->_statement,'setFetchMode'),$params);
        }

        /**
         * Advances the reader to the next row in a result set.
         * @return array|false the current row, false if no more row available
         */
        public function read()
        {
                return $this->_statement->fetch();
        }

        /**
         * Returns a single column from the next row of a result set.
         * @param int zero-based column index
         * @return mixed|false the column of the current row, false if no more row available
         */
        public function readColumn($columnIndex)
        {
                return $this->_statement->fetchColumn($columnIndex);
        }

        /**
         * Returns a single column from the next row of a result set.
         * @param string class name of the object to be created and populated
         * @param array list of column names whose values are to be passed as parameters in the constructor of the class being created
         * @return mixed|false the populated object, false if no more row of data available
         */
        public function readObject($className,$fields)
        {
                return $this->_statement->fetchObject($className,$fields);
        }

        /**
         * Reads the whole result set into an array.
         * @return array the result set (each array element represents a row of data).
         * An empty array will be returned if the result contains no row.
         */
        public function readAll()
        {
                return $this->_statement->fetchAll();
        }

        /**
         * Advances the reader to the next result when reading the results of a batch of statements.
         * This method is only useful when there are multiple result sets
         * returned by the query. Not all DBMS support this feature.
         */
        public function nextResult()
        {
                return $this->_statement->nextRowset();
        }

        /**
         * Closes the reader.
         * Any further data reading will result in an exception.
         */
        public function close()
        {
                $this->_statement->closeCursor();
                $this->_closed=true;
        }

        /**
         * @return boolean whether the reader is closed or not.
         */
        public function getIsClosed()
        {
                return $this->_closed;
        }

        /**
         * @return int number of rows contained in the result.
         * Note, most DBMS may not give a meaningful count.
         * In this case, use "SELECT COUNT(*) FROM tableName" to obtain the number of rows.
         */
        public function getRowCount()
        {
                return $this->_statement->rowCount();
        }

        /**
         * @return int the number of columns in the result set.
         * Note, even there's no row in the reader, this still gives correct column number.
         */
        public function getColumnCount()
        {
                return $this->_statement->columnCount();
        }

        /**
         * Resets the iterator to the initial state.
         * This method is required by the interface Iterator.
         * @throws TDbException if this method is invoked twice
         */
        public function rewind()
        {
                if($this->_index<0)
                {
                        $this->_row=$this->_statement->fetch();
                        $this->_index=0;
                }
                else
                        throw new TDbException('dbdatareader_rewind_invalid');
        }

        /**
         * Returns the index of the current row.
         * This method is required by the interface Iterator.
         * @return integer the index of the current row.
         */
        public function key()
        {
                return $this->_index;
        }

        /**
         * Returns the current row.
         * This method is required by the interface Iterator.
         * @return mixed the current row.
         */
        public function current()
        {
                return $this->_row;
        }

        /**
         * Moves the internal pointer to the next row.
         * This method is required by the interface Iterator.
         */
        public function next()
        {
                $this->_row=$this->_statement->fetch();
                $this->_index++;
        }

        /**
         * Returns whether there is a row of data at current position.
         * This method is required by the interface Iterator.
         * @return boolean whether there is a row of data at current position.
         */
        public function valid()
        {
                return $this->_row!==false;
        }
}