<?php
/* 
 *  $Id$
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.phpdoctrine.com>.
 */
Doctrine::autoload("Doctrine_Connection_Common");
/**
 * Doctrine_Connection_Sqlite
 *
 * @package     Doctrine ORM
 * @url         www.phpdoctrine.com
 * @license     LGPL
 */

class Doctrine_Connection_Sqlite extends Doctrine_Connection_Common { 
    /**
     * Return string to call a variable with the current timestamp inside an SQL statement
     * There are three special variables for current date and time.
     *
     * @return string       sqlite function as string
     */
    public function now($type = 'timestamp') {
        switch ($type) {
        case 'time':
            return 'time(\'now\')';
        case 'date':
            return 'date(\'now\')';
        case 'timestamp':
        default:
            return 'datetime(\'now\')';
        }
    }
    /**
     * Set the transacton isolation level.
     *
     * @param   string  standard isolation level
     *                  READ UNCOMMITTED (allows dirty reads)
     *                  READ COMMITTED (prevents dirty reads)
     *                  REPEATABLE READ (prevents nonrepeatable reads)
     *                  SERIALIZABLE (prevents phantom reads)
     * @return void
     */
    function setTransactionIsolation($isolation) {
        switch ($isolation) {
            case 'READ UNCOMMITTED':
                $isolation = 0;
                break;
            case 'READ COMMITTED':
            case 'REPEATABLE READ':
            case 'SERIALIZABLE':
                $isolation = 1;
                break;
            default:
            throw new Doctrine_Connection_Sqlite_Exception('Isolation level ' . $isolation . 'is not supported.');
        }

        $query = "PRAGMA read_uncommitted=$isolation";
        return $this->_doQuery($query, true);
    }
    /**
     * return string to call a function to get a substring inside an SQL statement
     *
     * @return string to call a function to get a substring
     * @access public
     */
    public function substring($value, $position = 1, $length = null) {
        if($length !== null)
            return "substr($value,$position,$length)";

        return "substr($value,$position,length($value))";
    }

    /**
     * return string to call a function to get random value inside an SQL statement
     *
     * @return string to generate float between 0 and 1
     */
    public function random()
    {
        return '((RANDOM() + 2147483648) / 4294967296)';
    }
}