PDO - Create .sql file using PHP and PDO

db_backup.php

<?php

/* 
	PDO - create .sql file with PHP using PDO.
	
	Either include the common.php file (which includes the db connection info), or connect to the db here.
	
	Check the first dozen or so following lines for options.
*/
	include("../common.php");

	//$db = new PDO("mysql:host=$db_hostname;dbname=$db_database; charset=utf8", $db_username, $db_password);



	//put table names you want backed up in this array.
	//leave empty to do all
	$tables = array();

	backup_tables($db, $tables);



	function backup_tables($db, $tables) {

	$db->setAttribute(PDO::ATTR_ORACLE_NULLS, PDO::NULL_NATURAL );

	//Script Variables
	$compression = true;
	$BACKUP_PATH = "db_backups/";
	$nowtimename = date('Y-m-d H.i.s',time());


	//create/open files
	if ($compression) {
	$zp = gzopen($BACKUP_PATH.$nowtimename.'.sql.gz', "a9");
	} else {
	$handle = fopen($BACKUP_PATH.$nowtimename.'.sql','a+');
	}


	//array of all database field types which just take numbers
	$numtypes=array('tinyint','smallint','mediumint','int','bigint','float','double','decimal','real');

	//get all of the tables
	if(empty($tables)) {
	$pstm1 = $db->query('SHOW TABLES');
	while ($row = $pstm1->fetch(PDO::FETCH_NUM)) {
	$tables[] = $row[0];
	}
	} else {
	$tables = is_array($tables) ? $tables : explode(',',$tables);
	}

	//cycle through the table(s)

	foreach($tables as $table) {
	$result = $db->query("SELECT * FROM $table");
	$num_fields = $result->columnCount();
	$num_rows = $result->rowCount();

	$return="";
	//uncomment below if you want 'DROP TABLE IF EXISTS' displayed
	$return.= 'DROP TABLE IF EXISTS `'.$table.'`;';


	//table structure
	$pstm2 = $db->query("SHOW CREATE TABLE $table");
	$row2 = $pstm2->fetch(PDO::FETCH_NUM);
	$ifnotexists = str_replace('CREATE TABLE', 'CREATE TABLE IF NOT EXISTS', $row2[1]);
	$return.= "\n\n".$ifnotexists.";\n\n";


	if ($compression) {
	gzwrite($zp, $return);
	} else {
	fwrite($handle,$return);
	}
	$return = "";

	//insert values
	if ($num_rows){
	$return= 'INSERT INTO `'."$table"."` (";
	$pstm3 = $db->query("SHOW COLUMNS FROM $table");
	$count = 0;
	$type = array();

	while ($rows = $pstm3->fetch(PDO::FETCH_NUM)) {

	if (stripos($rows[1], '(')) {$type[$table][] = stristr($rows[1], '(', true);
	} else $type[$table][] = $rows[1];

	$return.= "`".$rows[0]."`";
	$count++;
	if ($count < ($pstm3->rowCount())) {
	$return.= ", ";
	}
	}

	$return.= ")".' VALUES';

	if ($compression) {
	gzwrite($zp, $return);
	} else {
	fwrite($handle,$return);
	}
	$return = "";
	}
	$count =0;
	while($row = $result->fetch(PDO::FETCH_NUM)) {
	$return= "\n\t(";

	for($j=0; $j<$num_fields; $j++) {

	//$row[$j] = preg_replace("\n","\\n",$row[$j]);


	if (isset($row[$j])) {

	//if number, take away "". else leave as string
	if ((in_array($type[$table][$j], $numtypes)) && (!empty($row[$j]))) $return.= $row[$j] ; else $return.= $db->quote($row[$j]);

	} else {
	$return.= 'NULL';
	}
	if ($j<($num_fields-1)) {
	$return.= ',';
	}
	}
	$count++;
	if ($count < ($result->rowCount())) {
	$return.= "),";
	} else {
	$return.= ");";

	}
	if ($compression) {
	gzwrite($zp, $return);
	} else {
	fwrite($handle,$return);
	}
	$return = "";
	}
	$return="\n\n-- ------------------------------------------------ \n\n";
	if ($compression) {
	gzwrite($zp, $return);
	} else {
	fwrite($handle,$return);
	}
	$return = "";
	}



	$error1= $pstm2->errorInfo();
	$error2= $pstm3->errorInfo();
	$error3= $result->errorInfo();
	echo $error1[2];
	echo $error2[2];
	echo $error3[2];

	if ($compression) {
	gzclose($zp);
	} else {
	fclose($handle);
	}
	}
?>