Loading .sql files from within PHP

phpBB uses a few functions to parse their files. They are rather well-commented (what an exception!) so you can easily know what they do (I got this solution from http://www.frihost.com/forums/vt-8194.html). here is the solution an I've used it a lot:

<?php
ini_set('memory_limit', '5120M');
set_time_limit ( 0 );
/***************************************************************************
*                             sql_parse.php
*                              -------------------
*     begin                : Thu May 31, 2001
*     copyright            : (C) 2001 The phpBB Group
*     email                : [email protected]
*
*     $Id: sql_parse.php,v 1.8 2002/03/18 23:53:12 psotfx Exp $
*
****************************************************************************/

/***************************************************************************
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 ***************************************************************************/

/***************************************************************************
*
*   These functions are mainly for use in the db_utilities under the admin
*   however in order to make these functions available elsewhere, specifically
*   in the installation phase of phpBB I have seperated out a couple of
*   functions into this file.  JLH
*
\***************************************************************************/

//
// remove_comments will strip the sql comment lines out of an uploaded sql file
// specifically for mssql and postgres type files in the install....
//
function remove_comments(&$output)
{
$lines = explode("\n", $output);
$output = "";

// try to keep mem. use down
$linecount = count($lines);

$in_comment = false;
for($i = 0; $i < $linecount; $i++)
{
    if( preg_match("/^\/\*/", preg_quote($lines[$i])) )
    {
        $in_comment = true;
    }

    if( !$in_comment )
    {
        $output .= $lines[$i] . "\n";
    }

    if( preg_match("/\*\/$/", preg_quote($lines[$i])) )
    {
        $in_comment = false;
    }
}

unset($lines);
return $output;
}

//
// remove_remarks will strip the sql comment lines out of an uploaded sql file
//
function remove_remarks($sql)
{
$lines = explode("\n", $sql);

// try to keep mem. use down
$sql = "";

$linecount = count($lines);
$output = "";

for ($i = 0; $i < $linecount; $i++)
{
    if (($i != ($linecount - 1)) || (strlen($lines[$i]) > 0))
    {
        if (isset($lines[$i][0]) && $lines[$i][0] != "#")
        {
            $output .= $lines[$i] . "\n";
        }
        else
        {
            $output .= "\n";
        }
        // Trading a bit of speed for lower mem. use here.
        $lines[$i] = "";
    }
}

return $output;

}

//
// split_sql_file will split an uploaded sql file into single sql statements.
// Note: expects trim() to have already been run on $sql.
//
function split_sql_file($sql, $delimiter)
{
// Split up our string into "possible" SQL statements.
$tokens = explode($delimiter, $sql);

// try to save mem.
$sql = "";
$output = array();

// we don't actually care about the matches preg gives us.
$matches = array();

// this is faster than calling count($oktens) every time thru the loop.
$token_count = count($tokens);
for ($i = 0; $i < $token_count; $i++)
{
    // Don't wanna add an empty string as the last thing in the array.
    if (($i != ($token_count - 1)) || (strlen($tokens[$i] > 0)))
    {
        // This is the total number of single quotes in the token.
        $total_quotes = preg_match_all("/'/", $tokens[$i], $matches);
        // Counts single quotes that are preceded by an odd number of backslashes,
        // which means they're escaped quotes.
        $escaped_quotes = preg_match_all("/(?<!\\\\)(\\\\\\\\)*\\\\'/", $tokens[$i], $matches);

        $unescaped_quotes = $total_quotes - $escaped_quotes;

        // If the number of unescaped quotes is even, then the delimiter did NOT occur inside a string literal.
        if (($unescaped_quotes % 2) == 0)
        {
            // It's a complete sql statement.
            $output[] = $tokens[$i];
            // save memory.
            $tokens[$i] = "";
        }
        else
        {
            // incomplete sql statement. keep adding tokens until we have a complete one.
            // $temp will hold what we have so far.
            $temp = $tokens[$i] . $delimiter;
            // save memory..
            $tokens[$i] = "";

            // Do we have a complete statement yet?
            $complete_stmt = false;

            for ($j = $i + 1; (!$complete_stmt && ($j < $token_count)); $j++)
            {
            // This is the total number of single quotes in the token.
            $total_quotes = preg_match_all("/'/", $tokens[$j], $matches);
            // Counts single quotes that are preceded by an odd number of backslashes,
            // which means they're escaped quotes.
            $escaped_quotes = preg_match_all("/(?<!\\\\)(\\\\\\\\)*\\\\'/", $tokens[$j], $matches);

            $unescaped_quotes = $total_quotes - $escaped_quotes;

            if (($unescaped_quotes % 2) == 1)
            {
                // odd number of unescaped quotes. In combination with the previous incomplete
                // statement(s), we now have a complete statement. (2 odds always make an even)
                $output[] = $temp . $tokens[$j];

                // save memory.
                $tokens[$j] = "";
                $temp = "";

                // exit the loop.
                $complete_stmt = true;
                // make sure the outer loop continues at the right point.
                $i = $j;
            }
            else
            {
                // even number of unescaped quotes. We still don't have a complete statement.
                // (1 odd and 1 even always make an odd)
                $temp .= $tokens[$j] . $delimiter;
                // save memory.
                $tokens[$j] = "";
            }

            } // for..
        } // else
    }
}

return $output;
}

$dbms_schema = 'yourfile.sql';

$sql_query = @fread(@fopen($dbms_schema, 'r'), @filesize($dbms_schema)) or die('problem ');
$sql_query = remove_remarks($sql_query);
$sql_query = split_sql_file($sql_query, ';');

$host = 'localhost';
$user = 'user';
$pass = 'pass';
$db = 'database_name';

// mysql_* is deprecated, prefer using mysqli_* instead
// mysql_connect($host,$user,$pass) or die('error connection');
// mysql_select_db($db) or die('error database selection');
$connection = mysqli_connect($host,$user,$pass) or die('error connection');
mysqli_select_db($connection, $db) or die('error database selection');

$i=1;
foreach($sql_query as $sql){
    echo $i++;
    echo "<br />";
    // mysql_* is deprecated, prefer using mysqli_* instead
    // mysql_query($sql) or die('error in query');
    mysqli_query($connection, $sql) or die('error in query');
}

$db = new PDO($dsn, $user, $password);

$sql = file_get_contents('file.sql');

$qr = $db->exec($sql);