php数据库操作类(转)

<?php

Class DB {

    private $link_id;

    private $handle;

    private $is_log;

    private $time;

    //构造函数

    public function __construct() {

        $this->time = $this->microtime_float();

        require_once("config.db.php");

        $this->connect($db_config["hostname"], $db_config["username"], $db_config["password"], $db_config["database"], $db_config["pconnect"]);

        $this->is_log = $db_config["log"];

        if($this->is_log){

            $handle = fopen($db_config["logfilepath"]."dblog.txt", "a+");

            $this->handle=$handle;

        }

    }

    //数据库连接

    public function connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect = 0,$charset=‘utf8‘) {

        if( $pconnect==0 ) {

            $this->link_id = @mysql_connect($dbhost, $dbuser, $dbpw, true);

            if(!$this->link_id){

                $this->halt("数据库连接失败");

            }

        } else {

            $this->link_id = @mysql_pconnect($dbhost, $dbuser, $dbpw);

            if(!$this->link_id){

                $this->halt("数据库持久连接失败");

            }

        }

        if([email protected]_select_db($dbname,$this->link_id)) {

            $this->halt(‘数据库选择失败‘);

        }

        @mysql_query("set names ".$charset);

    }

    //查询

    public function query($sql) {

        $this->write_log("查询 ".$sql);

        $query = mysql_query($sql,$this->link_id);

        if(!$query) $this->halt(‘Query Error: ‘ . $sql);

        return $query;

    }

    //获取一条记录（MYSQL_ASSOC，MYSQL_NUM，MYSQL_BOTH）             

    public function get_one($sql,$result_type = MYSQL_ASSOC) {

        $query = $this->query($sql);

        $rt =& mysql_fetch_array($query,$result_type);

        $this->write_log("获取一条记录 ".$sql);

        return $rt;

    }

    //获取全部记录

    public function get_all($sql,$result_type = MYSQL_ASSOC) {

        $query = $this->query($sql);

        $i = 0;

        $rt = array();

        while($row =& mysql_fetch_array($query,$result_type)) {

            $rt[$i]=$row;

            $i++;

        }

        $this->write_log("获取全部记录 ".$sql);

        return $rt;

    }

    //插入

    public function insert($table,$dataArray) {

        $field = "";

        $value = "";

        if( !is_array($dataArray) || count($dataArray)<=0) {

            $this->halt(‘没有要插入的数据‘);

            return false;

        }

        while(list($key,$val)=each($dataArray)) {

            $field .="$key,";

            $value .="‘$val‘,";

        }

        $field = substr( $field,0,-1);

        $value = substr( $value,0,-1);

        $sql = "insert into $table($field) values($value)";

        $this->write_log("插入 ".$sql);

        if(!$this->query($sql)) return false;

        return true;

    }

    //更新

    public function update( $table,$dataArray,$condition="") {

        if( !is_array($dataArray) || count($dataArray)<=0) {

            $this->halt(‘没有要更新的数据‘);

            return false;

        }

        $value = "";

        while( list($key,$val) = each($dataArray))

        $value .= "$key = ‘$val‘,";

        $value .= substr( $value,0,-1);

        $sql = "update $table set $value where 1=1 and $condition";

        $this->write_log("更新 ".$sql);

        if(!$this->query($sql)) return false;

        return true;

    }

    //删除

    public function delete( $table,$condition="") {

        if( empty($condition) ) {

            $this->halt(‘没有设置删除的条件‘);

            return false;

        }

        $sql = "delete from $table where 1=1 and $condition";

        $this->write_log("删除 ".$sql);

        if(!$this->query($sql)) return false;

        return true;

    }

    //返回结果集

    public function fetch_array($query, $result_type = MYSQL_ASSOC){

        $this->write_log("返回结果集");

        return mysql_fetch_array($query, $result_type);

    }

    //获取记录条数

    public function num_rows($results) {

        if(!is_bool($results)) {

            $num = mysql_num_rows($results);

            $this->write_log("获取的记录条数为".$num);

            return $num;

        } else {

            return 0;

        }

    }

    //释放结果集

    public function free_result() {

        $void = func_get_args();

        foreach($void as $query) {

            if(is_resource($query) && get_resource_type($query) === ‘mysql result‘) {

                return mysql_free_result($query);

            }

        }

        $this->write_log("释放结果集");

    }

    //获取最后插入的id

    public function insert_id() {

        $id = mysql_insert_id($this->link_id);

        $this->write_log("最后插入的id为".$id);

        return $id;

    }

    //关闭数据库连接

    protected function close() {

        $this->write_log("已关闭数据库连接");

        return @mysql_close($this->link_id);

    }

    //错误提示

    private function halt($msg=‘‘) {

        $msg .= "\r\n".mysql_error();

        $this->write_log($msg);

        die($msg);

    }

    //析构函数

    public function __destruct() {

        $this->free_result();

        $use_time = ($this-> microtime_float())-($this->time);

        $this->write_log("完成整个查询任务,所用时间为".$use_time);

        if($this->is_log){

            fclose($this->handle);

        }

    }

    //写入日志文件

    public function write_log($msg=‘‘){

        if($this->is_log){

            $text = date("Y-m-d H:i:s")." ".$msg."\r\n";

            fwrite($this->handle,$text);

        }

    }

    //获取毫秒数

    public function microtime_float() {

        list($usec, $sec) = explode(" ", microtime());

        return ((float)$usec + (float)$sec);

    }

}

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<?php

    $db_config["hostname"] = "localhost"; //服务器地址

    $db_config["username"] = "root"; //数据库用户名

    $db_config["password"] = "123"; //数据库密码

    $db_config["database"] = "test"; //数据库名称

    $db_config["charset"] = "utf8";//数据库编码

    $db_config["pconnect"] = 1;//开启持久连接

    $db_config["log"] = 1;//开启日志

    $db_config["logfilepath"] = ‘./‘;//开启日志

?>