<?php

/**
 * This file is part of the Propel package.
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * @license    MIT License
 */

/**
 * This is used to connect to PostgresQL databases.
 *
 * <a href="http://www.pgsql.org">http://www.pgsql.org</a>
 *
 * @author     Hans Lellelid <hans@xmpl.org> (Propel)
 * @author     Hakan Tandogan <hakan42@gmx.de> (Torque)
 * @version    $Revision: 1909 $
 * @package    propel.runtime.adapter
 */
class DBPostgres extends DBAdapter
{

	/**
	 * This method is used to ignore case.
	 *
	 * @param      string $in The string to transform to upper case.
	 * @return     string The upper case string.
	 */
	public function toUpperCase($in)
	{
		return "UPPER(" . $in . ")";
	}

	/**
	 * This method is used to ignore case.
	 *
	 * @param      in The string whose case to ignore.
	 * @return     The string in a case that can be ignored.
	 */
	public function ignoreCase($in)
	{
		return "UPPER(" . $in . ")";
	}

	/**
	 * Returns SQL which concatenates the second string to the first.
	 *
	 * @param      string String to concatenate.
	 * @param      string String to append.
	 * @return     string
	 */
	public function concatString($s1, $s2)
	{
		return "($s1 || $s2)";
	}

	/**
	 * Returns SQL which extracts a substring.
	 *
	 * @param      string String to extract from.
	 * @param      int Offset to start from.
	 * @param      int Number of characters to extract.
	 * @return     string
	 */
	public function subString($s, $pos, $len)
	{
		return "substring($s from $pos" . ($len > -1 ? "for $len" : "") . ")";
	}

	/**
	 * Returns SQL which calculates the length (in chars) of a string.
	 *
	 * @param      string String to calculate length of.
	 * @return     string
	 */
	public function strLength($s)
	{
		return "char_length($s)";
	}

	/**
	 * @see        DBAdapter::getIdMethod()
	 */
	protected function getIdMethod()
	{
		return DBAdapter::ID_METHOD_SEQUENCE;
	}

	/**
	 * Gets ID for specified sequence name.
	 */
	public function getId(PDO $con, $name = null)
	{
		if ($name === null) {
			throw new PropelException("Unable to fetch next sequence ID without sequence name.");
		}
		$stmt = $con->query("SELECT nextval(".$con->quote($name).")");
		$row = $stmt->fetch(PDO::FETCH_NUM);
		return $row[0];
	}

	/**
	 * Returns timestamp formatter string for use in date() function.
	 * @return     string
	 */
	public function getTimestampFormatter()
	{
		return "Y-m-d H:i:s O";
	}

	/**
	 * Returns timestamp formatter string for use in date() function.
	 * @return     string
	 */
	public function getTimeFormatter()
	{
		return "H:i:s O";
	}

	/**
	 * @see        DBAdapter::applyLimit()
	 */
	public function applyLimit(&$sql, $offset, $limit)
	{
		if ( $limit > 0 ) {
			$sql .= " LIMIT ".$limit;
		}
		if ( $offset > 0 ) {
			$sql .= " OFFSET ".$offset;
		}
	}
	
	/**
	 * @see        DBAdapter::random()
	 */
	public function random($seed=NULL)
	{
		return 'random()';
	}
	
	/**
	 * @see        DBAdapter::getDeleteFromClause()
	 */
	public function getDeleteFromClause($criteria, $tableName)
	{
		$sql = 'DELETE ';
		if ($queryComment = $criteria->getComment()) {
			$sql .= '/* ' . $queryComment . ' */ ';
		}
		if ($realTableName = $criteria->getTableForAlias($tableName)) {
			if ($this->useQuoteIdentifier()) {
				$realTableName = $this->quoteIdentifierTable($realTableName);
			}
			$sql .= 'FROM ' . $realTableName . ' AS ' . $tableName;
		} else {
			if ($this->useQuoteIdentifier()) {
				$tableName = $this->quoteIdentifierTable($tableName);
			}
			$sql .= 'FROM ' . $tableName;
		}
		return $sql;
	}
}