mysql_fetch_object

(PHP 3, PHP 4, PHP 5)

mysql_fetch_object -- 从结果集中取得一行作为对象

说明

object mysql_fetch_object ( resource result )

返回根据所取得的行生成的对象,如果没有更多行则返回 FALSE

mysql_fetch_object()mysql_fetch_array() 类似,只有一点区别 - 返回一个对象而不是数组。间接地也意味着只能通过字段名来访问数组,而不是偏移量(数字是合法的属性名)。

注: 本函数返回的字段名是区分大小写的。

<?php

/* this is valid */
echo $row->field;
/* this is invalid */
echo $row->0;

?>

速度上,本函数和 mysql_fetch_array() 一样,也几乎和 mysql_fetch_row() 一样快(差别很不明显)。

例子 1. mysql_fetch_object() 例子

<?php
mysql_connect
("hostname", "user", "password");
mysql_select_db("mydb");
$result = mysql_query("select * from mytable");
while (
$row = mysql_fetch_object($result)) {
    echo
$row->user_id;
    echo
$row->fullname;
}
mysql_free_result($result);
?>

参见 mysql_fetch_array()mysql_fetch_assoc()mysql_fetch_row()


add a note add a note User Contributed Notes
syntax
22-Oct-2006 09:00
@Simon Paridon and others concerning SQL to php getting results via mysql_fetch_object:

Every query that would fail in a database frontend, such as MySQLs "Query Browser" and only will work by using the `-marks will probably give results hardly accessible in PHP especially if you have column names with "-" or " " in it.

Using the example of Simon Paridon: it is not possible to execute a query like:

SELECT id, user-id FROM unlucky_naming

only

SELECT id, `user-id` FROM unlucky_naming

will work...

so either be a bit wiser when naming the colums (e.g. user_id)

or try it with

SELECT id, `user-id` AS user_id FROM unlucky_naming

(i have not tested it in PHP yet, but i guess this will fail as well, if you have a query like "SELECT `foo name` FROM `unlucky naming 2`")

Somewhat down "amackenz at cs dot uml dot edu" mentioned to name sum, count etc. this may be a good hint for newbies: increase the speed of your php applications by using (my)sql native functions and save data transfer as well as processing time
Simon Paridon
24-Sep-2006 08:53
The behavior of this function is slightly questionable.

If you have a col in you table containing non-variable-name characters like "-", mysql_fetch_object will add "impossible variable names" to your object, e.g.

object (
  [user-id] => 7
)

You can not access this variable normally with $obj->user-id, because the variable name is invalid. But you can however access it like this:

$foo = 'user-id';
echo $obj->$foo;

It will correctly output 7, whereas var_dump($obj->user-id) would output int(0) for some reason.

I got this behaviour with PHP 4.4.2.
Kaminari (telecotxesco at hotmail)
24-Jul-2006 07:55
This is a very very elegant (and costless) way to fetch an enterie query to every single field name from a "wide" table:

The tedious way fetching:
<?php
   $idtable
=mysql_connect("localhost","user","pwd");
  
mysql_select_db("table",$idtable);
  
$consult=mysql_query("SELECT *
                           FROM models
                           ORDER BY Serie,Year ASC"
);
   while(
$row=mysql_fetch_object($consult)){
      
$IdLomo=$row->IdLomo;
      
$Serie=$row->Serie;
      
$Model=$row->Model;
      
$Type=$row->Type;
      
$Year=$row->Year;
      
$Speed=$row->Speed;
      
$Power=$row->Power;
      
$Price=$row->Price;
      
$Load1=$row->Load1;
      
$Load2=$row->Load2;
      
$Load3=$row->Load3;
      
$Load4=$row->Load4;
      
$Server=$row->Servier;
      
$Real=$row->Real;
      
$Lomo=$row->Lomo;
   }
?>

Resulting on 15 new variables called like their name on table wich we introduced manualy for 5 minutes. But imagine each row has 100 fields!

A way saving time with the same result:

<?php
   $idtable
=mysql_connect("localhost","user","pwd");
  
mysql_select_db("table",$idtable);
  
$consult=mysql_query("SELECT *
                           FROM models
                           ORDER BY Serie,Year ASC"
);
  
// We find the fields number
  
$numfields=mysql_num_fields($consult);

  
// Now we put the names of fields in a Array
  
for($i=0;$i<$numfields;$i++){
      
$fieldname[$i]=mysql_field_name($consult, $i);
   }

   while(
$row=mysql_fetch_object($consult)){
      
//Finally we assign the new variables
      
for($i=0;$i<$numfields;$i++){
           $
$fieldname[$i]=$row->$fieldname[$i];
       }
   }
?>
trithaithus at tibiahumor dot net
22-Aug-2005 04:56
This method offers a nice way to fetch objects from databases. As Federico at Pomi dot net mentioned it doesn't work native as the type of the object fetched isn't the right one, but with a small typecast it works flawlessly.

<?php
function ClassTypeCast(&$obj,$class_type){
   if(
class_exists($class_type)){
      
$obj = unserialize(preg_replace("/^O:[0-9]+:\\"[^"]+\\":/i",
         "
O:".strlen($class_type).":"".$class_type."\\":", serialize($obj)));
   }
}

class Foo
{
   var $foo;
   var $bar;
   function get_from_db()
   {
       mysql_connect();
       mysql_select_db();
       $res = mysql_query("
SELECT foo,bar from my_table");
      
       $fetched_object = mysql_fetch_object($res);
       ClassTypeCast($fetched_object,"
Foo");
       $this = $fetched_object;
   }
}
?>
backglancer at hotmail
07-Aug-2005 06:07
Watch out for mysql_fetch_object() to return all values as strings.
if you try to do
<?
$p
= mysql_fetch_object($some_sql);
// and then try to do something like

$money = $p->dollars + $p->cents;
?>

You may experience "Unsupported operand types"

so always cast them both as (int) 's!!
q
09-Jul-2004 10:31
Some clarifications about previous notes concerning duplicate field names in a result set.

Consider the following relations:

TABLE_A(id, name)
TABLE_B(id, name, id_A)

Where TABLE_B.id_A references TABLE_A.id.

Now, if we join these tables like this: "SELECT * FROM TABLE_A, TABLE_B WHERE TABLE_A.id = TABLE_B.id_A", the result set looks like this: (id, name, id, name, id_A).

The behaviour of mysql_fetch_object on a result like this isn't documented here, but it seems obvious that some data will be lost because of the duplicate field names.

This can be avoided, as Eskil Kvalnes stated, by aliasing the field names. However, it is not necessary to alias all fields on a large table, as the following syntax is legal in MySQL: "SELECT *, TABLE_A.name AS name_a, TABLE_B.name AS name_b FROM TABLE_A, TABLE_B ...". This will produce a result set formatted like this: (id, name, id, name, id_A, name_a, name_b), and your data is saved. Hooray!

-q
rcoles at hotmail dot com
16-Oct-2003 05:11
In reviewing Eskil Kvalnes's comments (04-Mar-2003 11:59
When using table joins in a query you obviously need to name all the fields to make it work right with mysql_fetch_object()) I was left asking and, as a newbie, the reason why I'm here. I have a 28 field table. Ran SELECT * with a LEFT JOIN, etc and it appears to have worked on my test server without issue.

On further reading, MYSQL.COM has the following:
* It is not allowed to use a column alias in a WHERE clause, because the column value may not yet be determined when the WHERE clause is executed. See section A.5.4 Problems with alias.
* The FROM table_references clause indicates the tables from which to retrieve rows. If you name more than one table, you are performing a join. For information on join syntax, see section 6.4.1.1 JOIN Syntax. For each table specified, you may optionally specify an alias.

Aware of the fact there's a difference between tables and fields there appears to be confusion here somewhere.
zhundiak at comcast dot net
16-May-2003 09:44
Here is a wrapper that will allow specifying a class name.
function &db_fetch_object($set,$className)
{
  /* Start by getting the usual array */
  $row = mysql_fetch_assoc($set);
  if ($row === null) return null;

  /* Create the object */
  $obj =& new $className();

  /* Explode the array and set the objects's instance data */
  foreach($row as $key => $value)
  {
   $obj->{$key} = $value;
  }
  return $obj;
}
class CPerson
{
  function getFullName()
  {
   return $this->fname . ' ' . $this->lname;
  }
}
$set = mysql_query('SELECT fname,lname FROM person');
while($person =& db_fetch_object($set,'CPerson'))
{
  echo $person->getFullName();
}
Eskil Kvalnes
04-Mar-2003 02:59
When using table joins in a query you obviously need to name all the fields to make it work right with mysql_fetch_object().
kalleanka
31-Jan-2003 07:50
an addition to the previous...

for example getting members from a database:

function getAllMembers () {
   $query = "SELECT * FROM people ORDER BY lname";
   $result = mysql_query($query);
          
   while($member = mysql_fetch_object($result)){
       $members[] = $member;
   }
                  
   return $members;
}
<br><br>
   DON'T FORGET TO DECLARE THE ARRAY. If you try to cycle through members after the function has been called and you don't declare the array first you will get a horribly (HORRIBLY!) ugly error in your page. Also, if you try to add the object into the members array inside the while condition instead of in the while loop, you will generate one extra empty space in the array due to the last iteration/check.
spamme at aol dot com
17-Jan-2003 04:28
This is probably a little more elegant:

$sql = "SELECT * FROM table ";
$result = mysql_query($sql);

$data = array();

while ($row = mysql_fetch_object($result))
   $data[] = $row;
allen at brooker dot gb dot net
19-Nov-2002 08:14
I found the above code to be buggy, not adding all the records to the array. This is the code I used instead:

  $command = "SELECT * FROM table ";
  $result = mysql_query($command, $link_id);
  $num = mysql_num_rows($result);

  $clickthru = array();

  for ($i = 0; $i <= $num; $i++) {
   $clickthru[$i] = array();
   $clickthru[$i] = mysql_fetch_array($result);
  }

Allen
Federico at Pomi dot net
15-Sep-2002 10:41
Be carefull:
the object returned will be a new/fresh object.

You can't use this function to replace some attributes of an existing object keeping the old ones.

Example:
class person
{
   var $name;
   var $surname;
   var $doh;

function print()
{
   print($name." ".$surname);
}

function get_from_db()
{
   $res=query("select name, surname from ppl where... limit 1");
   $this=mysql-fetch-object($res);
}

}

This won't work! When the method get_from_db() is executed, your old object will be destroyed... you won't find anything in the attribute $doh, and if you'll try to call the method print(), it will say it doesn't exist.
amackenz at cs dot uml dot edu
15-Jan-2001 03:03
When selecting with a count/sum, the field must be named.

select count(*) from users;
becomes
select count(*) as total from users;

This way the result can be referenced as:
$row->total;