<?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 in order to connect to a SQLite database.
 *
 * @author     Hans Lellelid <hans@xmpl.org>
 * @version    $Revision: 1612 $
 * @package    propel.runtime.adapter
 */
class DBSQLite extends DBAdapter
{

	/**
	 * For SQLite this method has no effect, since SQLite doesn't support specifying a character
	 * set (or, another way to look at it, it doesn't require a single character set per DB).
	 *
	 * @param      PDO   A PDO connection instance.
	 * @param      string The charset encoding.
	 * @throws     PropelException If the specified charset doesn't match sqlite_libencoding()
	 */
	public function setCharset(PDO $con, $charset)
	{
	}

	/**
	 * This method is used to ignore case.
	 *
	 * @param      in The string to transform to upper case.
	 * @return     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, $len)
	{
		return "substr($s, $pos, $len)";
	}

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

	/**
	 * @see        DBAdapter::quoteIdentifier()
	 */
	public function quoteIdentifier($text)
	{
		return '[' . $text . ']';
	}

	/**
	 * @see        DBAdapter::applyLimit()
	 */
	public function applyLimit(&$sql, $offset, $limit)
	{
		if ( $limit > 0 ) {
			$sql .= " LIMIT " . $limit . ($offset > 0 ? " OFFSET " . $offset : "");
		} elseif ( $offset > 0 ) {
			$sql .= " LIMIT -1 OFFSET " . $offset;
		}
	}

	public function random($seed=NULL)
	{
		return 'random()';
	}

}
