» Writing Functions with mysql_fetch_object() by Michael Milano
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Writing Functions with mysql_fetch_object
The title might be a little confusing, but I'm just going to explain the mysql_fetch_object() function. A lot of programmers are either intimidated or don't see a need to use 'objects' with PHP.
The reason I find this method very handy is so I don't have to re-write any functions in case I add/edit/remove a field in my database.
First I will show an example of how one might traditionally write a function to get user data from a table. This function will return an array.
Imagine we are using a database table with userid, firstname, and lastname.
PHP Code:
<?
function getUser($userid){
$array = array();
$result = mysql_query("select * from user where userid=".$userid);
if($row = mysql_fetch_array($result)){
$array['firstname'] = $row['firstname'];
$array['lastname'] = $row['lastname'];
}
return $array;
}
?>
What if we want to add an additional field, 'username', to the user table? Not only would we have to alter the database table, but we would have to modify our getUser() function.
I'll show you two ways to solve this. The first will be a method which I've used in the past. First, you describe the table to create an array of field names. Then you use that array to create the key names of your user array. Don't follow? Here is an example:
$array = array();
$result= mysql_query("select * from user where userid=".$userid);
if($row = mysql_fetch_array($result)){
foreach($fields as $field){
// create the key name from the field name array
$array[$field]=$row[$field];
}
}
return $array;
}
?>
With the example above, we would never have to modify the function if we modified the user table. The downside of this is that we execute 2 queries when we should really only need 1.
The mysql_fetch_object() method solves this problem if you don't mind working with objects. This mysql function assigns the field names as they are queried as properties of the object.
In short, instead of using $array['firstname'], you will use $object->firstname.
Below is an example of mysql_fetch_object().
PHP Code:
<?
function getUser($userid){
$result = mysql_query("select * from user where userid=".$userid);
// object will return false if there is no more rows
// since there is only 1 result possible with a userid
// i do not need this in a while loop.
$object = mysql_fetch_object($result);
return $object;
}
?>
Now let's look at an example when we would get multiple users in our result. The best way to do this is create an array of objects.
PHP Code:
<?
function getUsers(){
$result = mysql_query("select * from user");
// here is how we would use this
$user_array = getUsers();
foreach($user_array as $user_object){
echo $user_object->firstname . " " . $user_object->lastname . "<br>\n";
}
?>
Again, the purpose of doing it this way is so that you will never have to go back and modify this function in case you modify the database table.
I hope this article has been informative. Thanks for reading.
