while do not apply sql statements

[lofaifa]

this is working fine :

 

while($tags=mysql_fetch_array($d_b->sql_answer,MYSQL_ASSOC)){ 
echo $tags['tag_name'] . "<br/>";
}

 

display :

 

html
css
javascript
c++
php

 

but when i try to do some sql statements inside like this :

 

while($tags=mysql_fetch_array($d_b->sql_answer,MYSQL_ASSOC)){ 
$sql="SELECT * FROM user
		      WHERE user_languages LIKE '% {$tags[tag_name]} %'";

		//to apply the $sql
		$d_b->apply($sql);
//number of results
		$num=$d_b->num_rows();
		$sql="UPDATE tags 
		      SET tag_folowers={$num}";
		$d_b->apply($sql);
}

 

it return an error : Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given

[scootstah]

The error is because the query failed due to an error, and thus returned FALSE. You can see what the error is with mysql_error().

 

Also, putting queries inside loops is generally not a good idea. You can most likely do what you want with a single query.

[lofaifa]

its the same "$d_b->sql_answer" of example 1 , why is it working in case 1 and not the other ?

[scootstah]

I don't know, print the error and find out.

[lofaifa]

in fact $d_b->sql_answer==true .. now i dont know what to do its still a boolean as the error said

[PFMaBiSmAd]

The error message is most likely because your database class does not return a result resource/result object to the calling code, but instead holds the result of the query internally. This means that it cannot execute more than one query at a time and each query overwrites the result of the previous query.

 

What's the code of your database class?

[lofaifa]

<?php
require_once('config.php');
require_once('functions.php');
class mysqldb {
public  $result=array();
public $sql_answer;
private $connection; 
private $magic_quotes_active;
private $real_escape_string_active;
function __construct(){
	$this->open_connection();
	mysql_query("set names utf8");
	$this->magic_quotes_active=get_magic_quotes_gpc();
	$this->real_escape_string_active=function_exists("mysql_real_escape_string");
}
public function open_connection(){
	$this->connection=mysql_connect(DB_SERVER,DB_USER,DB_PASS);
	if(!$this->connection){
		die("Database connection failed: " . mysql_error());
	}
	else {
		$db_select=mysql_select_db(DB_NAME,$this->connection);
		if(!$db_select){
			die("Database selection failed: " . mysql_error());
		}
	}
}
public function close_connection(){
	if(isset($this->connection)){
		mysql_close($this->connection);
		unset($this->connection);
	}
}
public function clean($value){
	if($this->real_escape_string_active){
		if($this->magic_quotes_active){$value=stripslashes($value);}
		$value=mysql_real_escape_string($value);

	}else {
		if(!$this->magic_quotes_active){$value=addslashes($value);}
	}
	return $value;
}
public function apply($sql){
	$sql_answer=mysql_query($sql);
	if(!$sql_answer){

		die("your sql statement is wrong at the syntax side : " . $sql ); 
	}else{
		$this->sql_answer=$sql_answer;
		}
	}
public function get_results(){
	if($this->sql_answer){
	$this->result=mysql_fetch_array($this->sql_answer,MYSQL_ASSOC);
	}
	else{
		die("u didnt select anything at the first time");
	}	
}
public function num_rows(){
	$this->num_rows=mysql_num_rows($this->sql_answer);
	return mysql_num_rows($this->sql_answer);
}
public function clean_XSS($value){
	//should read about this functions soon;
	$value=htmlentities($value,ENT_COMPAT,'UTF-8');
	return $value;
}
}
$d_b=new mysqldb();
?>

[PFMaBiSmAd]

$this->sql_answer=$sql_answer;

 

^^^ The above line of code means that one instance of your database class cannot perform a second query until you are done using the data from a previous query.

 

You would either need to make a second instance of your database class or rewrite your code so that the result resource is returned to the calling code, which assigns it to a program variable and that calling code then simply uses that program variable in the mysql_xxxxxx statements that expect a result resource.

[lofaifa]

i understand the problem now .. thank u