discuz db 类

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<?php

/**

 * by mckee & www.phpddt.com

 * modified by discuz DB

 */

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private $host; //主机名

private $username; //用户名

private $password; //密码

private $dbname; //数据库名

private $conn; //链接资源

private $pconnect; //是否持久连接

private $charset; //数据库编码

public $histories; //保存执行的sql语句

public $querynum = 0;  //查询的次数

//构造函数,初始化时连接数据库

public function __construct($host, $username, $password, $dbname, $charset, $pconnect = 0){

    $this->host = $host;

    $this->username = $username;

    $this->password = $password;

    $this->dbname = $dbname;

    $this->charset = $charset;

    if($pconnect){

        if(!$this->conn = mysql_pconnect($this->host,$this->username,$this->password)){

            $this->halt(‘Cannot connect to mysql‘);

        }

    }else{

        if(!$this->conn = mysql_connect($this->host,$this->username,$this->password)){

            $this->halt(‘Cannot connect to mysql‘);

        }

    }

    mysql_select_db($this->dbname);

    mysql_query("SET NAMES {$this->charset}");

}

//使用mysql_unbuffered_query不会使用缓冲区，但是它也有缺点，比如你不能使用mysql_num_rows来取得它结果的数量。

function query($sql, $type = ‘‘, $cachetime = FALSE) {

    $func = $type == ‘UNBUFFERED‘ && @function_exists(‘mysql_unbuffered_query‘) ? ‘mysql_unbuffered_query‘ : ‘mysql_query‘;

    if(!($query = $func($sql, $this->conn)) && $type != ‘SILENT‘) {

        $this->halt(‘MySQL Query Error‘, $sql);

    }

    $this->querynum++;

    $this->histories[] = $sql;

    return $query;

}

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//默认返回关联数组

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

    return mysql_fetch_array($query, $result_type);

}

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//返回第一行第一列

function result_first($sql) {

    $query = $this->query($sql);

    return $this->result($query, 0);

}

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//返回第一行数据

function fetch_first($sql) {

    $query = $this->query($sql);

    return $this->fetch_array($query);

}

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function fetch_all($sql, $id = ‘‘) {

    $arr = array();

    $query = $this->query($sql);

    while($data = $this->fetch_array($query)) {

        $id ? $arr[$data[$id]] = $data : $arr[] = $data;

    }

    return $arr;

}

function affected_rows() {

    return mysql_affected_rows($this->conn);

}

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function error() {

    return (($this->conn) ? mysql_error($this->conn) : mysql_error());

}

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function errno() {

    return intval(($this->conn) ? mysql_errno($this->conn) : mysql_errno());

}

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function result($query, $row) {

    $query = @mysql_result($query, $row);

    return $query;

}

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function num_rows($query) {

    $query = mysql_num_rows($query);

    return $query;

}

   //返回字段的数目

function num_fields($query) {

    return mysql_num_fields($query);

}

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function free_result($query) {

    return mysql_free_result($query);

}

//如果 AUTO_INCREMENT 的列的类型是 BIGINT，则 mysql_insert_id() 返回的值将不正确,但是可以用LAST_INSERT_ID() 来替代

function insert_id() {

    return ($id = mysql_insert_id($this->conn)) >= 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0);

}

function fetch_row($query) {

    $query = mysql_fetch_row($query);

    return $query;

}

//取得列信息

function fetch_fields($query) {

    return mysql_fetch_field($query);

}

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function version() {

    return mysql_get_server_info($this->conn);

}

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function close() {

    return mysql_close($this->conn);

}

//中断提示

public function halt($message = ‘‘, $sql = ‘‘){

    $error = mysql_error();

    $errorno = mysql_errno();

    $s = ‘‘;

    if($message) {

        $s = "<b>Error info:</b> $message<br />";

    }

    if($sql) {

        $s .= ‘<b>SQL:</b>‘.htmlspecialchars($sql).‘<br />‘;

    }

    $s .= ‘<b>Error:</b>‘.$error.‘<br />‘;

    $s .= ‘<b>Errno:</b>‘.$errorno.‘<br />‘;

    exit($s);

}