Mysql 数据库访问类

/**
* @purpose: mysql数据库访问类
* @package:
* @author: [e-mail]
* @modifications:
* @see:
* @time: 2008.10.10
*/
class db_mysql
{
//============================================================
private $host = 'localhost';
private $database = 'db_name';
private $user = 'user';
private $password = 'password';
//============================================================
private $link_id = 0; //数据库连接
private $query_id = 0; //查询结果
private $row_result = array(); //结果集组成的数组
private $field_result = array(); //结果集字段组成的数组
private $affected_rows; //影响的行数
private $rows; //结果集中记录的行数
private $fields; //结果集中字段数
private $row_postion = 0; //记录指针位置索引
public $insert_id = 0;
//************************************************************
/**** 构造函数 ****/
function __construct()
{
$this->connect();
}
/**** 析构函数 ****/
function __destruct()
{
@mysql_free_result($this->query_id);
mysql_close($this->link_id);
}
/**** 连接服务器,选择数据库 ****/
function connect($database = '',$host = '',$user = '',$password = '')
{
$database = $database == '' ? $this->database : $database;
$host = $host == '' ? $this->host : $host;
$user = $user == '' ? $this->user : $user;
$password = $password == '' ? $this->password : $password;
//-----------------------------------------------------------//
if(0 == $this->link_id)
{
$this->link_id = @mysql_pconnect($host,$user,$password);
if(!$this->link_id)
{
$this->halt('连接数据库服务端失败!');
}
if(!mysql_select_db($this->database,$this->link_id))
{
$this->halt('不能打开指定的数据库：'.$this->database);
}
}
return $this->link_id;
}
/**** 释放内存 ****/
function free()
{
if(@mysql_free_result($this->query_id))
{
unset($this->row_result);
}
$this->query_id = 0;
}
/**** 执行查询 ****/
function query($query_string)
{
//释放上次查询内存
if($this->query_id)
{
$this->free();
}
if(0 == $this->link_id)
{
$this->connect();
}
//设置中文字符集
@mysql_query('set names gb2312');
$this->query_id = mysql_query($query_string,$this->link_id);
$this->insert_id = mysql_insert_id();
if(!$this->query_id)
{
$this->halt('sql查询语句出错：'.$query_string);
}
@mysql_query('set names gb2312');
return $this->query_id;
}
/**** 将结果集指针指向指定行 ****/
function seek($pos)
{
if(@mysql_data_seek($this->query_id,$pos))
{
$this->row_position = $pos;
return true;
}
else
{
$this->halt('定位结果集发生错误!');
return false;
}
}
/**** 返回结果集组成的数组 ****/
function get_rows_array()
{
$this->get_rows();
for($i = 0; $i < $this->rows; $i++)
{
if(!mysql_data_seek($this->query_id,$i))
{
$this->halt('mysql_data_seek 查询出错!');
}
$this->row_result[$i] = mysql_fetch_array($this->query_id);
}
return $this->row_result;
}
/**** 返回结果集字段组成的数组 ****/
function get_fields_array()
{
$this->get_fields();
for($i = 0; $i < $this->fields; $i++)
{
$obj = mysql_fetch_field($this->query_id,$i);
$this->field_result[$i] = $obj->name;
}
return $this->field_result;
}
/**** 返回影响记录数 ****/
function get_affected_rows()
{
$this->affected_rows = mysql_affected_rows($this->link_id);
return $this->affected_rows;
}
/**** 返回结果集中的记录数 ****/
function get_rows()
{
$this->rows = mysql_num_rows($this->query_id);
return $this->rows;
}
/**** 返回结果集中的字段个数 ****/
function get_fields()
{
$this->fields = mysql_num_fields($this->query_id);
return $this->fields;
}
/**** 执行sql语句并返回由查询结果中第一行记录组成的数组 ****/
function fetch_one_array($sql)
{ @mysql_query('set names gb2312');
$this->query($sql);
return mysql_fetch_array($this->query_id);
}
/**** 打印错误信息 ****/
function halt($msg)
{
$this->error = mysql_error();
printf("<font style='font-family:arial,宋体;font-size:12px;'> <b>数据库发生错误：</b> %s \n",$msg);
printf("mysql 返回错误信息：</b> %s \n",$this->error);
printf("错误页面：<font style='color:#0000ee;text-decoration:underline'>%s</font> \n",$_server['php_self']);
printf(" 请将错误信息提交到系统管理员或网站程序员处理! \n");
die('<b><font color=red>脚本终止</font></b></font>');
}
}