mysqli_result::fetch_fields
As indicated in the user comments of the mysql_fetch_object, it is important to realize that class fields get values assigned to them BEFORE the constructor is called.
For example;
<?php
class Employee
{
private $id;
public function __construct($id = 0)
{
$this->id = $id;
}
}
// some code for creating a database connection... i.e. mysqli object
....
$result = $con->query("select id, name from employees");
$anEmployee = $result->fetch_object("Employee");
?>
will result in the ID being 0 because it is overridden by the constructor. Therefore, it is useful to check if the class field is already set.
I.e.
<?php
class Employee
{
private $id;
public function __construct($id = 0)
{
if (!$this->id)
{
$this->id = $id
}
}
}
?>
Also note that the fields which will be assigned by fetch_object are case sensitive. If your table has the field "ID", it will result in the class field $ID being set. A simple work-around is to use aliases. I.e. "SELECT *, ID as id FROM myTable"
I hope this helps some people.
mysqli_result::fetch_object
mysqli_fetch_object
(PHP 5)
mysqli_result::fetch_object -- mysqli_fetch_object — Returns the current row of a result set as an object
Description
Object oriented style
object mysqli_result::fetch_object
([ string
$class_name
[, array $params
]] )Procedural style
The mysqli_fetch_object() will return the current row result set as an object where the attributes of the object represent the names of the fields found within the result set.
Note that mysqli_fetch_object() sets the properties of the object before calling the object constructor.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
-
class_name -
The name of the class to instantiate, set the properties of and return. If not specified, a stdClass object is returned.
-
params -
An optional array of parameters to pass to the constructor for
class_nameobjects.
Return Values
Returns an object with string properties that corresponds to the fetched
row or NULL if there are no more rows in resultset.
Note: Field names returned by this function are case-sensitive.
Note: This function sets NULL fields to the PHP
NULLvalue.
Changelog
| Version | Description |
|---|---|
| 5.0.0 | Added the ability to return as a different object. |
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = $mysqli->query($query)) {
/* fetch object array */
while ($obj = $result->fetch_object()) {
printf ("%s (%s)\n", $obj->Name, $obj->CountryCode);
}
/* free result set */
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = mysqli_query($link, $query)) {
/* fetch associative array */
while ($obj = mysqli_fetch_object($result)) {
printf ("%s (%s)\n", $obj->Name, $obj->CountryCode);
}
/* free result set */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Pueblo (USA) Arvada (USA) Cape Coral (USA) Green Bay (USA) Santa Clara (USA)
See Also
- mysqli_fetch_array() - Fetch a result row as an associative, a numeric array, or both
- mysqli_fetch_assoc() - Fetch a result row as an associative array
- mysqli_fetch_row() - Get a result row as an enumerated array
- mysqli_query() - Performs a query on the database
- mysqli_data_seek() - Adjusts the result pointer to an arbitrary row in the result
add a note
User Contributed Notes
mysqli_result::fetch_object - [5 notes]
Driek ¶
10 months ago
benpptung at tacol dot biz ¶
3 years ago
I don't know why no one talk about this.
fetch_object is very powerful since you can instantiate an Object which has the methods you wanna have.
You can try like this..
<?php
class PowerfulVO extends AbstractWhatEver {
public $field1;
private $field2; // note : private is ok
public function method(){
// method in this class
}
}
$sql = "SELECT * FROM table ..."
$mysqli = new mysqli(........);
$result = $mysqli->query($sql);
$vo = $result->fetch_object('PowerfulVO');
?>
Note : if the field is not defined in the class, fetch_object will add this field for you as public.
The method is very powerful, especially if you want to use a VO design pattern or class mapping feature with Flex Remoting Object( Of course, you need to have ZendAMF or AMFPHP ..framework)
Hope this help and open new possibilities for you
jorortega at gmail dot com ¶
9 months ago
Be aware that, since the class fields get values assigned to them BEFORE the constructor is called, the...
if ($result = $mysqli->query($query)) {
...statement in some cases has not sense. At all.
Using some example:
$query = "SELECT * FROM City WHERE Country='some country'";
If 'some country' doesn't exist, $query won't be FALSE like with the good old days, but will be an object with some predefined fields. Thus, in this case, the if statement is useles, as it will always be TRUE.
In this case, is best to check the object property "num_rows" :
if ($result->num_rows != 0) ...
because if the query fails, num_rows will be asigned the number 0 (integer), and thus, you will know the query failed.
Alex ¶
1 year ago
Make sure to specify the full namespace for the "string $class_name" parameter and not a partial one, as it won't find it. For example:
<?php
namespace Root(backslash)FirstLevel
{
public static function Test($result)
{
return mysqli_fetch_object($result, 'SecondLevel\\MyClass');
}
}
?>
... will not work but this will:
<?php
namespace Root(backslash)FirstLevel
{
public static function Test($result)
{
return mysqli_fetch_object($result, 'Root\\FirstLevel\\SecondLevel\\MyClass');
}
}
?>
peterbelm at g[oogle]mail dot com ¶
4 years ago
If your SQL code selects columns with empty names like so:
SELECT id as ``...
You will get a fatal error "Cannot access empty property", this took me a while to track down!
Obviously your SQL really shouldn't do that, and should be fixed but I'm going to submit a feature request to ask for a better error message for that.