PHP访问MYSQL数据库封装类
<?php
/*
MYSQL 数据库访问封装类
MYSQL 数据访问方式，php4支持以mysql_开头的过程访问方式，php5开始支持以mysqli_开头的过程和mysqli面向对象
访问方式，本封装类以mysql_封装
数据访问的一般流程：
1,连接数据库 mysql_connect or mysql_pconnect
2,选择数据库 mysql_select_db
3,执行SQL查询 mysql_query
4,处理返回的数据 mysql_fetch_array mysql_num_rows mysql_fetch_assoc mysql_fetch_row etc
*/
class db_mysql
{
var $querynum = 0 ; //当前页面进程查询数据库的次数
var $dblink ; //数据库连接资源
//链接数据库
function connect($dbhost,$dbuser,$dbpw,$dbname='',$dbcharset='utf-8',$pconnect=0 , $halt=true)
{
$func = empty($pconnect) ? 'mysql_connect' : 'mysql_pconnect' ;
$this->dblink = @$func($dbhost,$dbuser,$dbpw) ;
if ($halt && !$this->dblink)
{
$this->halt("无法链接数据库！");
}
//设置查询字符集
mysql_query("SET character_set_connection={$dbcharset},character_set_results={$dbcharset},character_set_client=binary",$this->dblink) ;
//选择数据库
$dbname && @mysql_select_db($dbname,$this->dblink) ;
}
//选择数据库
function select_db($dbname)
{
return mysql_select_db($dbname,$this->dblink);
}
//执行SQL查询
function query($sql)
{
$this->querynum++ ;
return mysql_query($sql,$this->dblink) ;
}
//返回最近一次与连接句柄关联的INSERT，UPDATE 或DELETE 查询所影响的记录行数
function affected_rows()
{
return mysql_affected_rows($this->dblink) ;
}
//取得结果集中行的数目,只对select查询的结果集有效
function num_rows($result)
{
return mysql_num_rows($result) ;
}
//获得单格的查询结果
function result($result,$row=0)
{
return mysql_result($result,$row) ;
}
//取得上一步 INSERT 操作产生的 ID,只对表有AUTO_INCREMENT ID的操作有效
function insert_id()
{
return ($id = mysql_insert_id($this->dblink)) >= 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0);
}
//从结果集提取当前行，以数字为key表示的关联数组形式返回
function fetch_row($result)
{
return mysql_fetch_row($result) ;
}
//从结果集提取当前行，以字段名为key表示的关联数组形式返回
function fetch_assoc($result)
{
return mysql_fetch_assoc($result);
}
//从结果集提取当前行，以字段名和数字为key表示的关联数组形式返回
function fetch_array($result)
{
return mysql_fetch_array($result);
}
//关闭链接
function close()
{
return mysql_close($this->dblink) ;
}
//输出简单的错误html提示信息并终止程序
function halt($msg)
{
$message = "<html>\n<head>\n" ;
$message .= "<meta content='text/html;charset=gb2312'>\n" ;
$message .= "</head>\n" ;
$message .= "<body>\n" ;
$message .= "数据库出错：".htmlspecialchars($msg)."\n" ;
$message .= "</body>\n" ;
$message .= "</html>" ;
echo $message ;
exit ;
}
}
?>
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