php reads txt file and inserts data into database

DM00001A11 0116,
SN00002A11 0116,
AB00003A11 0116,
PV00004A11 0116,
OC00005A11 0116,
IX00006A11 0116,

create table serial_number(
id int primary key auto_increment not null,
serial_number varchar(50) not null
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

$conn = mysql_connect('127.0.0.1','root','') or die("Invalid query: " . mysql_error());
mysql_select_db('test', $conn) or die("Invalid query: " . mysql_error());

$content = file_get_contents("serial_number.txt");
$c//explode()函数以","为标识符进行拆分

foreach ($contents as $k => $v)//遍历循环
{
  $id = $k;
  $serial_number = $v;
  mysql_query("insert into serial_number (`id`,`serial_number`)
      VALUES('$id','$serial_number')");
}

<&#63;php
/**
 * $splitChar 字段分隔符
 * $file 数据文件文件名
 * $table 数据库表名
 * $conn 数据库连接
 * $fields 数据对应的列名
 * $insertType 插入操作类型，包括INSERT,REPLACE
 */
function loadTxtDataIntoDatabase($splitChar,$file,$table,$conn,$fields=array(),$insertType='INSERT'){
  if(empty($fields)) $head = "{$insertType} INTO `{$table}` VALUES('";
  else $head = "{$insertType} INTO `{$table}`(`".implode('`,`',$fields)."`) VALUES('";  //数据头
  $end = "')";
  $sqldata = trim(file_get_contents($file));
  if(preg_replace('/\s*/i','',$splitChar) == '') {
    $splitChar = '/(\w+)(\s+)/i';
    $replace = "$1','";
    $specialFunc = 'preg_replace';
  }else {
    $splitChar = $splitChar;
    $replace = "','";
    $specialFunc = 'str_replace';
  }
  //处理数据体，二者顺序不可换，否则空格或Tab分隔符时出错
  $sqldata = preg_replace('/(\s*)(\n+)(\s*)/i','\'),(\'',$sqldata);  //替换换行
  $sqldata = $specialFunc($splitChar,$replace,$sqldata);        //替换分隔符
  $query = $head.$sqldata.$end;  //数据拼接
  if(mysql_query($query,$conn)) return array(true);
  else {
    return array(false,mysql_error($conn),mysql_errno($conn));
  }
}

//调用示例1
require 'db.php';
$splitChar = '|';  //竖线
$file = 'sqldata1.txt';
$fields = array('id','parentid','name');
$table = 'cengji';
$result = loadTxtDataIntoDatabase($splitChar,$file,$table,$conn,$fields);
if (array_shift($result)){
  echo 'Success!<br/>';
}else {
  echo 'Failed!--Error:'.array_shift($result).'<br/>';
}
/*sqlda ta1.txt
1|0|A
2|1|B
3|1|C
4|2|D

-- cengji
CREATE TABLE `cengji` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `parentid` int(11) NOT NULL,
 `name` varchar(255) DEFAULT NULL,
 PRIMARY KEY (`id`),
 UNIQUE KEY `parentid_name_unique` (`parentid`,`name`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=1602 DEFAULT CHARSET=utf8
*/

//调用示例2
require 'db.php';
$splitChar = ' ';  //空格
$file = 'sqldata2.txt';
$fields = array('id','make','model','year');
$table = 'cars';
$result = loadTxtDataIntoDatabase($splitChar,$file,$table,$conn,$fields);
if (array_shift($result)){
  echo 'Success!<br/>';
}else {
  echo 'Failed!--Error:'.array_shift($result).'<br/>';
}
/* sqldata2.txt
11 Aston DB19 2009
12 Aston DB29 2009
13 Aston DB39 2009

-- cars
CREATE TABLE `cars` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `make` varchar(16) NOT NULL,
 `model` varchar(16) DEFAULT NULL,
 `year` varchar(16) DEFAULT NULL,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=utf8
*/

//调用示例3
require 'db.php';
$splitChar = '  ';  //Tab
$file = 'sqldata3.txt';
$fields = array('id','make','model','year');
$table = 'cars';
$insertType = 'REPLACE';
$result = loadTxtDataIntoDatabase($splitChar,$file,$table,$conn,$fields,$insertType);
if (array_shift($result)){
  echo 'Success!<br/>';
}else {
  echo 'Failed!--Error:'.array_shift($result).'<br/>';
}
/* sqldata3.txt
11  Aston  DB19  2009
12  Aston  DB29  2009
13  Aston  DB39  2009 
*/

//调用示例3
require 'db.php';
$splitChar = '  ';  //Tab
$file = 'sqldata3.txt';
$fields = array('id','value');
$table = 'notExist';  //不存在表
$result = loadTxtDataIntoDatabase($splitChar,$file,$table,$conn,$fields);
if (array_shift($result)){
  echo 'Success!<br/>';
}else {
  echo 'Failed!--Error:'.array_shift($result).'<br/>';
}

//附：db.php
/*  //注释这一行可全部释放
?>
<&#63;php
static $connect = null;
static $table = 'jilian';
if(!isset($connect)) {
  $connect = mysql_connect("localhost","root","");
  if(!$connect) {
    $connect = mysql_connect("localhost","Zjmainstay","");
  }
  if(!$connect) {
    die('Can not connect to database.Fatal error handle by /test/db.php');
  }
  mysql_select_db("test",$connect);
  mysql_query("SET NAMES utf8",$connect);
  $conn = &$connect;
  $db = &$connect;
}
&#63;>

CREATE TABLE `100000_insert` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `parentid` int(11) NOT NULL,
 `name` varchar(255) DEFAULT NULL,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8