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应用MYSQLI读取数据库读不了问题

程序员文章站 2022-05-29 16:36:31
...
 host = $host;      if ($user != "") $this -> user = $user;      if ($pass != "") $this -> pass = $pass;      if ($database != "") $this -> database = $database;	       if (!$this -> conn = @mysqli_connect($this -> host, $this -> user, $this -> pass))	  {        return $this -> output("连接数据库 '".$this -> host."' 失败。".mysqli_error($this -> conn));      }	   mysqli_query($this -> conn,"SET NAMES 'utf8'");       $this -> selectdb();    }function selectdb($database="")	{      if ($database != "" && $database != $this -> database)        $this -> database = $database;      if (!mysqli_select_db($this -> conn, $this -> database))	  {        return $this -> output("无法使用数据库 '".$this -> database."'。");      }	}function query($sql="", $database="")                     //$sql	{      if ($sql != "") $this -> sql = $sql;      if ($database != "" && $database != $this -> database)	  {        $olddb = $this -> database;        $this -> selectdb($database);      }      $this -> result = @mysqli_query($this -> conn,$this -> sql);      if (mysqli_error($this -> conn) != "")	  {        return $this -> output("执行以下SQL语句时失败:'".$this -> sql."' 

".mysqli_error($this -> conn)); } $this -> n = @mysqli_affected_rows($this -> conn); if (!empty($olddb)) $this -> selectdb($olddb); return $this -> result; }function get_data() { /* if(!$this -> result || !preg_match("/^Resource/i", $this -> result)){ */ if(!$this -> result || !is_resource($this->result)){ return $this->output("没有数据,请先执行SQL的'select'语句!"); } $count=0; $this -> m = @mysqli_num_rows($this -> result); if ($this -> m > 0) { while ($row = mysqli_fetch_array($this -> result)) { $data[$count] = $row; $count++; } return $this->result=$data; } else { return $this -> output("数据为空!"); } mysqli_free_result($this -> result); }function output($msg){ $this->err=$msg; if ($this->debug)echo $msg; return false;} }?>////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////"; echo "
"; } $sql = "SELECT * FROM t6_dept where de_id>'0' ORDER BY de_id ASC"; $db -> query($sql); $result = $db -> get_data(); if(!$result) { echo "取出数据失败result 0"; echo "
"; echo "
"; }echo $result[0]["de_name"]; //无法显示数据print_r($db);?>


最后输出不了数据$resul没有值 t浏览器显示结果:求哪里出错了 ???

链接数据库 1

取出数据失败result 0

mysqldb Object ( [host] => localhost [user] => root [pass] => 1234 [database] => t6_db_hp [conn] => mysqli Object ( [affected_rows] => 4 [client_info] => mysqlnd 5.0.11-dev - 20120503 - $Id: f373ea5dd5538761406a8022a4b8a374418b240e $ [client_version] => 50011 [connect_errno] => 0 [connect_error] => [errno] => 0 [error] => [error_list] => Array ( ) [field_count] => 4 [host_info] => localhost via TCP/IP [info] => [insert_id] => 0 [server_info] => 5.6.20 [server_version] => 50620 [stat] => Uptime: 22428 Threads: 1 Questions: 5 Slow queries: 0 Opens: 68 Flush tables: 1 Open tables: 61 Queries per second avg: 0.000 [sqlstate] => 00000 [protocol_version] => 10 [thread_id] => 1 [warning_count] => 0 ) [sql] => SELECT * FROM t6_dept where de_id>'0' ORDER BY de_id ASC [n] => 4 [m] => 0 [result] => mysqli_result Object ( [current_field] => 0 [field_count] => 4 [lengths] => [num_rows] => 4 [type] => 0 ) [debug] => [err] => 没有数据,请先执行SQL的'select'语句! )


回复讨论(解决方案)

mysqli_query($this -> conn,$this -> sql) 返回的是 mysqli_result 对象,不是 resource (资源)
所以 !is_resource($this->result) 成立,程序提前结束

mysqli_query($this -> conn,$this -> sql) 返回的是 mysqli_result 对象,不是 resource (资源)
所以 !is_resource($this->result) 成立,程序提前结束



要怎么改???

if(!$this -> result || !is_object($this->result)){
return $this->output("没有数据,请先执行SQL的'select'语句!");
}

if(!$this -> result || !is_object($this->result)){
return $this->output("没有数据,请先执行SQL的'select'语句!");
}



终于解决了困扰很多天的问题了,谢谢版主