php serialize

[chaiwei]

Hi,

 

I was thinking using serialization to reduce my database field.

 

eg.

I got a dog object with attribute (name , age , owner).

So I got a database table ( dog_table )

with field (id , name , age ,owner).

 

<?
class dog {

     private $name;
     private $age;
     private $owner;

     function __construct($in_name="unnamed",$in_age="0",$in_owner="unknown") {
         $this->name = $in_name;
         $this->age = $in_age;
         $this->owner = $in_owner;
     }

     function getage() {
         return ($this->age * 365);
     }
     
     function getowner() {
         return ($this->owner);
     }
     
     function getname() {
         return ($this->name);
     }

    function save() {
        mysql_query("INSERT INTO dog_table VALUES( null , 'getname()' , 'getage()' , 'getowner()' )");
    }
}
?>


$bob = new dog('bob' , 2 , 'john');
$bob->save();

 

with serialization, I can change my table structure to:

database table ( dog_table )

field (id , dogObject )

 

remain the class,

add one more function ->  dogObjSerialize() 

and modify the save function.

 

 
<?
class dog {

     private $name;
     private $age;
     private $owner;
    private $dogObj;

     function __construct($in_name="unnamed",$in_age="0",$in_owner="unknown") {
         $this->name = $in_name;
         $this->age = $in_age;
         $this->owner = $in_owner;
     }

     function getage() {
         return ($this->age * 365);
     }
     
     function getowner() {
         return ($this->owner);
     }
     
     function getname() {
         return ($this->name);
     }

    function dogObjSerialize($obj){
        $this->dogObj = $obj;
    }

     function save() {
         mysql_query("INSERT INTO dog_table VALUES( null , '$this->dogObj' )");
     }
}
?>


$bob = new dog('bob' , 2 , 'john');
$bob->dogObjSerialize(serialize($bob));
$bob->save();

 

Is this way better?

[Daniel0]

No, for a table to be even 1NF (1st normal form) in database normalization it's a requirement that each field is atomic, that's to say it contains only one thing and it cannot be broken down any further.

[chaiwei]

hmmm,not understand.

because from what I see, It is easier to retrieve the value.

example,

 

mysql_query("INSERT INTO dog_table VALUES( null , '$this->dogObj' )");
$dogObj = mysql_fetch_array(mysql_query("SELECT * FROM dog_table WHERE id=1"));

$dog = unserialize($dogObj['dogObject']);

 

like this I can straight use $dog->getname();

 

I don't have to :

 mysql_query("INSERT INTO dog_table VALUES( null , '$this->dogObj' )");
  $dogObj = mysql_fetch_array(mysql_query("SELECT * FROM dog_table WHERE id=1"));

$this->name=$dogObj['name'];
$this->age=$dogObj['age'];

[Daniel0]

But how would you then retrieve all dogs that are older than 2 years? That's why atomicity is a requirement for normalized database schemas.

 

In the dog table, one row should already represent one dog, so having a dog inside the dog doesn't make sense. If you want to represent the dog as an object in PHP you could write a simple ORM (object-relational mapper) or use an existing one such as Doctrine.