$result = $Db->Query("DELETE FROM `table` WHERE `column` = '".mysql_real_escape_string($_GET["file"])
."' LIMIT 1";

// retrieve file into a string
$txt = file_get_contents('toApprove.txt');
// replace the line with $_GET["file"], assuming line break is \n
$txt = str_replace(trim($_GET["file"])."\n", '', $txt);
// write the string back to the file
file_put_contents('toApprove.txt', $txt);

// retrieve the file into an array where each line is a value
$Array = file('toApprove.txt');
// assuming unique values, lets remove the Array key with value $_GET["file"]
unset($Array[array_search(trim($_GET["file"]), $Array)]);
// explode the array into string with line breaks seperation and put everthing back in the file
file_put_contents('toApprove.txt', implode("\n", $Array));

if (!file_exists('file_put_contents')) {
// create a simple user function to emulate PHP5's file_put_contents() 
function file_put_contents($file, $contents) {
fwrite($fp = fopen($file), $contents, strlen($contents));
fclose($fp);
}
}

// retrieve file into a string
$txt = file_get_contents('database.txt');
// replace the line with $_GET["file"], assuming line break is \n
$txt = str_replace(trim($_GET["info"]),'', $txt);
// strip out any empty lines
$txt = preg_replace('/^\n+|^[\t\s]*\n+/m','',$txt);
// write the string back to the file
file_put_contents('database.txt', $txt);

<?php
 
/*
 * Create a new SplFileObject representation of the file
 * Open it for reading and writing and place the pointer at the beginning of the file
 * @see fopen for additional modes
 */
$file = new SplFileObject('database.txt', 'a+');
 
/*
 * Set a bitmask of the flags to apply - Only relates to reading from file
 * In this case SplFileObject::DROP_NEW_LINE to remove new line charachters
 * and SplFileObject::SKIP_EMPTY to remove empty lines
 */
$file->setFlags(7);
 
/*
 * Lock the file so no other user can interfere with reading and writing while we work with it
 */
$file->flock(LOCK_EX);
 
/*
 * Create a SplTempFileObject
 * 0 indicates not to use memory to store the temp file.
 * This is probably slower than using memory, but for a large file it will be much more effective
 * than loading the entire file into memory
 * @see http://www.php.net/manual/en/spltempfileobject.construct.php for more details
 */
$temp = new SplTempFileObject(0);
 
/*
 * Lock the temp file just in case
 */
$temp->flock(LOCK_EX);
 
/*
 * The line we're hoping to match and remove
 * DO NOT include any line ending charachters these have been stripped already
 */
$delete = 'Some line to match and delete.';
 
/*
 * Iterate over each line of the file only loading one line into memory at any point in time
 * Use trim() on the line to ensure we don't have excess whitespace anywhere
 */
foreach( $file as $line ){	
 
	if( trim($line) != $delete )
	{
		/*
		 * If this line does NOT match out delete write it to the temp file
		 * Append a line ending to it
		 */
		$temp->fwrite($line.PHP_EOL);
	} 
}
 
/*
 * Truncate the existing file to 0
 */
$file->ftruncate(0);
 
 
/*
 * Write the temp file back to the existing file
 */
foreach( $temp as $line ){
 
	/*
	 * Iterate over temp file and put each line back into original file
	 */
	$file->fwrite($line);
}
 
/*
 * Release the file locks
 */
$temp->flock(LOCK_UN);
$file->flock(LOCK_UN);

// Delete line 6 (Files start as 0, 1, 2, 3, etc like arrays)
$delete = 5;
 
/*
 * Iterate over each line and check its key
 */
foreach( $file as $key => $line ){	
 
	if( $key != $delete )
	{
		/*
		 * If this line does NOT match out delete write it to the temp file
		 * Append a line ending to it
		 */
		$temp->fwrite($line.PHP_EOL);
	} 
}