<?php
//////////////////////////////////////////////////////////////////////////
// + $Id$
// +------------------------------------------------------------------+ //
// + Cake PHP : Rapid Development Framework <http://www.cakephp.org/> + //
// + Copyright: (c) 2005, CakePHP Authors/Developers                  + //
// + Author(s): Michal Tatarynowicz aka Pies <tatarynowicz@gmail.com> + //
// +            Larry E. Masters aka PhpNut <nut@phpnut.com>          + //
// +            Kamil Dzielinski aka Brego <brego.dk@gmail.com>       + //
// +------------------------------------------------------------------+ //
// + Licensed under The MIT License                                   + //
// + Redistributions of files must retain the above copyright notice. + //
// + See: http://www.opensource.org/licenses/mit-license.php          + //
//////////////////////////////////////////////////////////////////////////

/**
  * PostgreSQL layer for DBO.
  * 
  * @filesource 
  * @author CakePHP Authors/Developers
  * @copyright Copyright (c) 2005, CakePHP Authors/Developers
  * @link https://trac.cakephp.org/wiki/Authors Authors/Developers
  * @package cake
  * @subpackage cake.libs
  * @since CakePHP v 1.0.0.114
  * @version $Revision$
  * @modifiedby $LastChangedBy$
  * @lastmodified $Date$
  * @license http://www.opensource.org/licenses/mit-license.php The MIT License
  */

/**
  * Include DBO.
  */
uses('dbo');

/**
  * PostgreSQL layer for DBO.
  *
  * @package cake
  * @subpackage cake.libs
  * @since CakePHP v 1.0.0.114
  */
class DBO_Postgres extends DBO 
{
	
/**
  * Connects to the database using options in the given configuration array.
  *
  * @param array $config Configuration array for connecting
  * @return True if successfully connected.
  */
	function connect ($config) 
	{
		if ($config) 
		{
			$this->config = $config;
			$this->_conn = pg_pconnect("host={$config['host']} dbname={$config['database']} user={$config['login']} password={$config['password']}");
		}
		$this->connected = $this->_conn? true: false;

		if($this->connected)
			return true;
		else
			die('Could not connect to DB.');
	}

/**
  * Disconnects from database.
  *
  * @return boolean True if the database could be disconnected, else false
  */
	function disconnect () 
	{
		return pg_close($this->_conn);
	}

/**
  * Executes given SQL statement.
  *
  * @param string $sql SQL statement
  * @return resource Result resource identifier
  */
	function execute ($sql) 
	{
		return pg_query($this->_conn, $sql);
	}

/**
  * Returns a row from given resultset as an array .
  *
  * @return array The fetched row as an array
  */
	function fetchRow () 
	{
		 return pg_fetch_array();
	}

/**
  * Returns an array of tables in the database. If there are no tables, an error is raised and the application exits.
  *
  * @return array Array of tablenames in the database
  */
	function tablesList () 
	{
		$sql = "SELECT a.relname AS name
         FROM pg_class a, pg_user b
         WHERE ( relkind = 'r') and relname !~ '^pg_' AND relname !~ '^sql_'
         AND relname !~ '^xin[vx][0-9]+' AND b.usesysid = a.relowner
         AND NOT (EXISTS (SELECT viewname FROM pg_views WHERE viewname=a.relname));";

		$result = $this->all($sql);

		if (!$result) 
		{
			trigger_error(ERROR_NO_TABLE_LIST, E_USER_ERROR);
			exit;
		}
		else 
		{
			$tables = array();
			foreach ($result as $item) $tables[] = $item['name'];
			return $tables;
		}
	}

/**
  * Returns an array of the fields in given table name.
  *
  * @param string $table_name Name of database table to inspect
  * @return array Fields in table. Keys are name and type
  */
	function fields ($table_name)
	{
		$sql = "SELECT c.relname, a.attname, t.typname FROM pg_class c, pg_attribute a, pg_type t WHERE c.relname = '{$table_name}' AND a.attnum > 0 AND a.attrelid = c.oid AND a.atttypid = t.oid";
		
		$fields = false;
		foreach ($this->all($sql) as $field) {
			$fields[] = array(
				'name' => $field['attname'],
				'type' => $field['typname']);
		}

		return $fields;
	}

/**
  * Returns a quoted and escaped string of $data for use in an SQL statement.
  *
  * @param string $data String to be prepared for use in an SQL statement
  * @return string Quoted and escaped
  */
	function prepareValue ($data)
	{
		return "'".pg_escape_string($data)."'";
	}

/**
  * Returns a formatted error message from previous database operation.
  *
  * @return string Error message
  */
	function lastError () 
	{
		$last_error = pg_last_error($this->_result);
		return $last_error? $last_error: null;
	}

/**
  * Returns number of affected rows in previous database operation. If no previous operation exists, this returns false.
  *
  * @return int Number of affected rows
  */
	function lastAffected ()
	{
		return $this->_result? pg_affected_rows($this->_result): false;
	}

/**
  * Returns number of rows in previous resultset. If no previous resultset exists, 
  * this returns false.
  *
  * @return int Number of rows in resultset
  */
	function lastNumRows () 
	{
		return $this->_result? pg_num_rows($this->_result): false;
	}

/**
  * Returns the ID generated from the previous INSERT operation.
  *
  * @param string $table Name of the database table
  * @param string $field Name of the ID database field. Defaults to "id"
  * @return int 
  */
	function lastInsertId ($table, $field='id') 
	{
		$sql = "SELECT CURRVAL('{$table}_{$field}_seq') AS max";
		$res = $this->rawQuery($sql);
		$data = $this->fetchRow($res);
		return $data['max'];
	}

	/**
	 * Returns a limit statement in the correct format for the particular database.
	 *
	 * @param int $limit Limit of results returned
	 * @param int $offset Offset from which to start results
	 * @return string SQL limit/offset statement
	 */
	function selectLimit ($limit, $offset=null)
	{
		return " LIMIT {$limit}".($offset? " OFFSET {$offset}": null);
	}

}

?>