我正在编写一个类和一些函数来连接数据库并从表中检索信息。我浏览过以前有类似标题的帖子，但大多数都是使用mysql函数编写的，我使用的是mysqli函数。
我希望有人可以通过这个简单的脚本让我知道我在哪里弄错了。
这是我的class.connect.php：
<?php
class mySQL{
var $host;
var $username;
var $password;
var $database;
public $dbc;
public function connect($set_host, $set_username, $set_password, $set_database)
{
$this->host = $set_host;
$this->username = $set_username;
$this->password = $set_password;
$this->database = $set_database;
$this->dbc = mysqli_connect($this->host, $this->username, $this->password, $this->database) or die('Error connecting to DB');
}
public function query($sql)
{
return mysqli_query($this->dbc, $sql) or die('Error querying the Database');
}
public function fetch($sql)
{
$array = mysqli_fetch_array($this->query($sql));
return $array;
}
public function close()
{
return mysqli_close($this->dbc);
}
}
?>
这是我的index.php：
<?php
require_once ("class.connect.php");
$connection = new mySQL();
$connection->connect('localhost', 'myDB', 'joker', 'names_list');
$myquery = "SELECT * FROM list";
$query = $connection->query($myquery);
while($array = $connection->fetch($query))
{
echo $array['first_name'] . '<br />';
echo $array['last_name'] . '<br />';
}
$connection->close();
?>
我收到的错误是Error querying the Database。
答案 0 :(得分：2)
几个问题： -
如果没有提供proper mysql error你就不会死（并且优雅地退出是好的做法）
fetch method只是FETCH的第一行
mysqli有OO方法，为什么你仍然使用程序功能？
答案 1 :(得分：2)
问题是：
public function fetch($sql)
{
$array = mysqli_fetch_array($this->query($sql));
return $array;
}
或者这个：
while($array = $connection->fetch($query))
因为您正在使用查询中的结果再次进行查询。基本上，你在做：
$r = mysqli_query($this->dbc, $sql);
$array = mysqli_fetch_array(mysqli_query($this->dbc, $r));
您收到错误，因为$ r不是查询字符串。当它被转换为字符串时，它是一个“1”（来自你的其他评论）。
尝试将函数更改为（更改变量名称，以便您可以看到差异）：
public function fetch($result)
{
return mysqli_fetch_array($result);
}
或直接调用该函数。
答案 2 :(得分：2)
如果你没有自己的db抽象来学习php和mysql，你可以使用Medoo（http://medoo.in/）。
这是一个免费的小型数据库框架，可以节省大量的工作和时间。
答案 3 :(得分：1)
SELECT * FROM list显然发生了错误，您可以使用mysqli_error查找错误：
return mysqli_query($this->dbc, $sql) or die('Error:'.mysqli_error($this->dbc));
这将显示确切的错误消息，并将帮助您解决问题。
答案 4 :(得分：1)
尝试检查
https://pramodjn2.wordpress.com/
$database = new db();
$query = $database->select(‘user’);
$st = $database->result($query);
print_r($st);
class db {
public $server = ‘localhost';
public $user = ‘root';
public $passwd = ‘*****';
public $db_name = ‘DATABASE NAME';
public $dbCon;
public function __construct(){
$this->dbCon = mysqli_connect($this->server, $this->user, $this->passwd, $this->db_name);
}
public function __destruct(){
mysqli_close($this->dbCon);
}
/* insert function table name, array value
$values = array(‘first_name’ => ‘pramod’,’last_name’=> ‘jain’);
*/
public function insert($table,$values)
{
$sql = “INSERT INTO $table SET “;
$c=0;
if(!empty($values)){
foreach($values as $key=>$val){
if($c==0){
$sql .= “$key='”.htmlentities($val, ENT_QUOTES).”‘”;
}else{
$sql .= “, $key='”.htmlentities($val, ENT_QUOTES).”‘”;
}
$c++;
}
}else{
return false;
}
$this->dbCon->query($sql) or die(mysqli_error());
return mysqli_insert_id($this->dbCon);
}
/* update function table name, array value
$values = array(‘first_name’ => ‘pramod’,’last_name’=> ‘jain’);
$condition = array(‘id’ =>5,’first_name’ => ‘pramod!’);
*/
public function update($table,$values,$condition)
{
$sql=”update $table SET “;
$c=0;
if(!empty($values)){
foreach($values as $key=>$val){
if($c==0){
$sql .= “$key='”.htmlentities($val, ENT_QUOTES).”‘”;
}else{
$sql .= “, $key='”.htmlentities($val, ENT_QUOTES).”‘”;
}
$c++;
}
}
$k=0;
if(!empty($condition)){
foreach($condition as $key=>$val){
if($k==0){
$sql .= ” WHERE $key='”.htmlentities($val, ENT_QUOTES).”‘”;
}else{
$sql .= ” AND $key='”.htmlentities($val, ENT_QUOTES).”‘”;
}
$k++;
}
}else{
return false;
}
$result = $this->dbCon->query($sql) or die(mysqli_error());
return $result;
}
/* delete function table name, array value
$where = array(‘id’ =>5,’first_name’ => ‘pramod’);
*/
public function delete($table,$where)
{
$sql = “DELETE FROM $table “;
$k=0;
if(!empty($where)){
foreach($where as $key=>$val){
if($k==0){
$sql .= ” where $key='”.htmlentities($val, ENT_QUOTES).”‘”;
}else{
$sql .= ” AND $key='”.htmlentities($val, ENT_QUOTES).”‘”;
}
$k++;
}
}else{
return false;
}
$del = $result = $this->dbCon->query($sql) or die(mysqli_error());
if($del){
return true;
}else{
return false;
}
}
/* select function
$rows = array(‘id’,’first_name’,’last_name’);
$where = array(‘id’ =>5,’first_name’ => ‘pramod!’);
$order = array(‘id’ => ‘DESC’);
$limit = array(20,10);
*/
public function select($table, $rows = ‘*’, $where = null, $order = null, $limit = null)
{
if($rows != ‘*’){
$rows = implode(“,”,$rows);
}
$sql = ‘SELECT ‘.$rows.’ FROM ‘.$table;
if($where != null){
$k=0;
foreach($where as $key=>$val){
if($k==0){
$sql .= ” where $key='”.htmlentities($val, ENT_QUOTES).”‘”;
}else{
$sql .= ” AND $key='”.htmlentities($val, ENT_QUOTES).”‘”;
}
$k++;
}
}
if($order != null){
foreach($order as $key=>$val){
$sql .= ” ORDER BY $key “.htmlentities($val, ENT_QUOTES).””;
}
}
if($limit != null){
$limit = implode(“,”,$limit);
$sql .= ” LIMIT $limit”;
}
$result = $this->dbCon->query($sql);
return $result;
}
public function query($sql){
$result = $this->dbCon->query($sql);
return $result;
}
public function result($result){
$row = $result->fetch_array();
$result->close();
return $row;
}
public function row($result){
$row = $result->fetch_row();
$result->close();
return $row;
}
public function numrow($result){
$row = $result->num_rows;
$result->close();
return $row;
}
}
答案 5 :(得分：1)
fetch方法中的mysqli_fetch_array函数需要两个参数，即SQL结果和要返回的数组类型。在我的情况下，我使用MYSQLI_ASSOC。
这应该是这样的：
公共函数提取（$ sql）
{
$ array = mysqli_fetch_array（$ this-＆gt; query（$ sql），MYSQLI_ASSOC）;
return $ array;
}
答案 6 :(得分：-1)
**classmysql.inc.php**
<?php
class dbclass {
var $CONN;
function dbclass() { //constructor
$conn = mysql_connect(SERVER_NAME,USER_NAME,PASSWORD);
//$conn = mysql_connect(localhost,root,"","");
if(!$conn)
{ $this->error("Connection attempt failed"); }
if(!mysql_select_db(DB_NAME,$conn))
{ $this->error("Database Selection failed"); }
$this->CONN = $conn;
return true;
}
//_____________close connection____________//
function close(){
$conn = $this->CONN ;
$close = mysql_close($conn);
if(!$close){
$this->error("Close Connection Failed"); }
return true;
}
function error($text) {
$no = mysql_errno();
$msg = mysql_error();
echo "<hr><font face=verdana size=2>";
echo "<b>Custom Message :</b> $text<br><br>";
echo "<b>Error Number :</b> $no<br><br>";
echo "<b>Error Message :</b> $msg<br><br>";
echo "<hr></font>";
exit;
}
//_____________select records___________________//
function select ($sql=""){
if(empty($sql)) { return false; }
if(!eregi("^select",$sql)){
echo "Wrong Query<hr>$sql<p>";
return false; }
if(empty($this->CONN)) { return false; }
$conn = $this->CONN;
$results = @mysql_query($sql,$conn);
if((!$results) or empty($results)) { return false; }
$count = 0;
$data = array();
while ( $row = mysql_fetch_array($results)) {
$data[$count] = $row;
$count++; }
mysql_free_result($results);
return $data;
}
//________insert record__________________//
function insert ($sql=""){
if(empty($sql)) { return false; }
if(!eregi("^insert",$sql)){ return false; }
if(empty($this->CONN)){ return false; }
$conn = $this->CONN;
$results = @mysql_query($sql,$conn);
if(!$results){
$this->error("Insert Operation Failed..<hr>$sql<hr>");
return false; }
$id = mysql_insert_id();
return $id;
}
//___________edit and modify record___________________//
function edit($sql="") {
if(empty($sql)) { return false; }
if(!eregi("^update",$sql)){ return false; }
if(empty($this->CONN)){ return false; }
$conn = $this->CONN;
$results = @mysql_query($sql,$conn);
$rows = 0;
$rows = @mysql_affected_rows();
return $rows;
}
//____________generalize for all queries___________//
function sql_query($sql="") {
if(empty($sql)) { return false; }
if(empty($this->CONN)) { return false; }
$conn = $this->CONN;
$results = mysql_query($sql,$conn) or $this->error("Something wrong in query<hr>$sql<hr>");
if(!$results){
$this->error("Query went bad ! <hr>$sql<hr>");
return false; }
if(!eregi("^select",$sql)){return true; }
else {
$count = 0;
$data = array();
while ( $row = mysql_fetch_array($results))
{ $data[$count] = $row;
$count++; }
mysql_free_result($results);
return $data;
}
}
function extraqueries($sql="") {
if(empty($sql)) { return false; }
if(empty($this->CONN)) { return false; }
$conn = $this->CONN;
$results = mysql_query($sql,$conn) or $this->error("Something wrong in query<hr>$sql<hr>");
if(!$results){
$this->error("Query went bad ! <hr>$sql<hr>");
return false; }
else {
$count = 0;
$data = array();
while ( $row = mysql_fetch_array($results))
{ $data[$count] = $row;
$count++; }
mysql_free_result($results);
return $data;
}
}
}
?>
**config.inc.php**
<?php
ini_set("memory_limit","70000M");
ini_set('max_execution_time', 900);
ob_start();
session_start();
error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED);
############################################
# Database Server
############################################
if($_SERVER['HTTP_HOST']=="localhost")
{
define("DB_NAME","DB_NAME");
define("SERVER_NAME","SERVER_NAME");
define("USER_NAME","USER_NAME");
define("PASSWORD","PASSWORD");
}
else
{
define("DB_NAME","DB_NAME");
define("SERVER_NAME","SERVER_NAME");
define("USER_NAME","USER_NAME");
define("PASSWORD","PASSWORD");
}
#############################################
# File paths
#############################################
// For the Database file path
include("system/classmysql.inc.php");
//For the inc folders
define("INC","inc/");
//For the Function File of the pages folders
define("FUNC","func/");
//For the path of the system folder
define("SYSTEM","system/");
$table_prefix = 'dep_';
################################################################
# Database Class
################################################################
$obj_db = new dbclass();
?>
**Function Page**
<?php
// IF admin is not logged in
if(!isset($_SESSION['session_id']))
{
header("location:index.php");
}
$backpage = 'page.php?type=staff&';
if(isset($_REQUEST['endbtn']) && trim($_REQUEST['endbtn']) == "Back")
{
header("location:".$backpage);
die();
}
// INSERT into database.
if(isset($_REQUEST['submit']) && trim($_REQUEST['submit']) == "Submit")
{
$pass = addslashes(trim($_REQUEST['password']));
$password = encrypt($pass, "deppro");
$username = addslashes(trim($_REQUEST['username']));
$sql = "select * from ".$table_prefix."users where `UserName` ='".$username."'";
$result = $obj_db->select($sql);
if(count($result) == 0)
{
$insert="INSERT INTO ".$table_prefix."users (`UserName`)VALUES ('".$username."')";
$sql=$obj_db->insert($insert);
$newuserid = mysql_insert_id($obj_db->CONN);
}
header("location:".$backpage."msg=send&alert=2");
die();
}
// DELETE record from database
if(isset($_REQUEST['action']) && trim($_REQUEST['action'])==3)
{
if(isset($_REQUEST['id']) && trim($_REQUEST['id']!=""))
{
$id = site_Decryption($_REQUEST['id']);
$sql_del = "Delete from ".$table_prefix."users where StaffID ='$id'";
$del = $obj_db->sql_query($sql_del);
header("location:".$backpage."msg=delete&alert=2");
die();
}
}
// UPDATE the record
$action=1;
if((isset($_REQUEST['action']) && trim($_REQUEST['action'])==2) && (!(isset($_REQUEST['submit']) && trim($_REQUEST['submit']) == "Submit")))
{
if(isset($_REQUEST['id']) && trim($_REQUEST['id']!=""))
{
$id = site_Decryption($_REQUEST['id']);
//$id = $_SESSION['depadmin_id'];
$sql = "select * from ".$table_prefix."users where StaffID ='$id'";
$result = $obj_db->select($sql);
if($result)
{
foreach($result as $row)
{
$title = stripslashes($row['StaffTitle']);
$action=2;
}
}
if(isset($_REQUEST['submit']) && trim($_REQUEST['submit']) == "Update")
{
$title = addslashes(trim($_REQUEST['title']));
$sql_upd ="UPDATE ".$table_prefix."users SET `StaffTitle` = '$title' WHERE StaffID ='$id'";
$result = $obj_db->sql_query($sql_upd);
$action=1;
header("location:".$backpage."msg=edited&alert=2");
die();
}
}
}
if(isset($_REQUEST['vid']) && trim($_REQUEST['vid']!=""))
{
$id = site_Decryption($_REQUEST['vid']);
$sql = "select * from ".$table_prefix."users where StaffID ='$id'";
$result = $obj_db->select($sql);
if($result)
{
foreach($result as $row)
{
$username = stripslashes($row['UserName']);
}
}
}
?>
<td class="center"><a href="cproperty.php?script=edit&action=2&id=<?php echo site_Encryption($sql[$j]['PropertyID']); ?>"><span class="editbutton"> </span></a> <a href="cproperty.php?action=3&id=<?php echo site_Encryption($sql[$j]['PropertyID']); ?>" onClick="return confirm('Are you sure to delete?');"><span class="deletebutton"> </span></a> <a class="lightbox" title="View" href="cpropertyview.php?script=view&vid=<?php echo site_Encryption($sql[$j]['PropertyID']); ?>&lightbox[width]=55p&lightbox[height]=60p"><span class="viewbutton"> </span></a></td>