Objects or not ?

Hi,

Im having a discussion with a friend about Objects.

Let say I create a user Object

class User
{
private $_aUserdata;
rivate $_sId;

function __construct($id)
{
$this->_sId=$id;
$this->_aUserdata= db::select('SELECT * FROM users WHERE UserId ="'.
$id.'"');
}

public function getName()
{
return $this->_aUserdata['firstnamename'].' '.$this-
>_aUserdata['lastname'];
}

function __destruct()
{
// just for this example
echo 'UPDATING USER';
$db::update('UPDATE users SET' lastsused="NOW()" WHERE UserId="'.$this-
>_sId.'"' );
}

}

Now i can have easy access to the users

$user=new User(1);
echo $user->getName();

// Arjen
// UPDATING USER

But no script I ever write is this simple.
Lets says that I want to select all forum entries and display the user
name along with the other data

$forumdata=$db::select('SELECT * FROM forum INNER JOIN USERS on
forum.UserId=users.UserId');

Now my userclass is completely useless because I allready have all the
data I need and I dont want to do another xxx select queries to the
user database. However i would still like to use User::getName()
because I might do some fancy calculation there and i dont want to
multpily my code. I now also dont have access to (the complpetely
useless) destructor so I have to update this manually.

How would I go and solve such a problem ?

I could imagine that I could loop through the forumdata and load the
user data into a new user object but is that really a good
solution ?

Arjen

Re: Objects or not ?

> I could imagine that I could loop through the forumdata and load the
> user data into a new user object but is that really a good
> solution ?

Have a look at Propel or Doctrine.

Re: Objects or not ?

floortje4@gmail.com wrote:
> Hi,
>
> Im having a discussion with a friend about Objects.
>
> Let say I create a user Object
>
> class User
> {
> private $_aUserdata;
> rivate $_sId;
>
> function __construct($id)
> {
> $this->_sId=$id;
> $this->_aUserdata= db::select('SELECT * FROM users WHERE UserId ="'.
> $id.'"');
> }
>
> public function getName()
> {
> return $this->_aUserdata['firstnamename'].' '.$this-
>> _aUserdata['lastname'];
> }
>
> function __destruct()
> {
> // just for this example
> echo 'UPDATING USER';
> $db::update('UPDATE users SET' lastsused="NOW()" WHERE UserId="'.$this-
>> _sId.'"' );
> }
>
> }
>
> Now i can have easy access to the users
>
> $user=new User(1);
> echo $user->getName();
>
> // Arjen
> // UPDATING USER
>
> But no script I ever write is this simple.
> Lets says that I want to select all forum entries and display the user
> name along with the other data
>
> $forumdata=$db::select('SELECT * FROM forum INNER JOIN USERS on
> forum.UserId=users.UserId');
>
> Now my userclass is completely useless because I allready have all the
> data I need and I dont want to do another xxx select queries to the
> user database. However i would still like to use User::getName()
> because I might do some fancy calculation there and i dont want to
> multpily my code. I now also dont have access to (the complpetely
> useless) destructor so I have to update this manually.
>
> How would I go and solve such a problem ?
>
> I could imagine that I could loop through the forumdata and load the
> user data into a new user object but is that really a good
> solution ?
>
> Arjen
>
>

First of all, don't do the select in your code. Let your objects do it.

In this case, create a userlist class and let it perform the select
statement, building a new userobject for each row.


--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

Re: Objects or not ?

On 13 nov, 14:40, Jerry Stuckle wrote:

Hi Jerry,

> First of all, don't do the select in your code. Let your objects do it.

Yup just trying to make the point without producing tons of code :-)

> In this case, create a userlist class and let it perform the select
> statement, building a new userobject for each row.

Maybe I dont understand you but is what im trying to avoid. Lets say
$aData contains 1000 rows with unique UserId's. Then this code would
produce 1001 select queries.

function CreateUserObj()
{
$aData=$db::select('SELECT UserId FROM forum');

foreach ($aData as $val)
{
// executes a new select statement
$aUserObj[$val['UserId']]=new User($val['UserId']);
}

return $aUserObj;
}

Re: Objects or not ?

On 13 nov, 14:27, Jonas Werres wrote:
> > I could imagine that I could loop through the forumdata and load the
> > user data into a new user object but is that really a good
> > solution ?
>
> Have a look at Propel or Doctrine

Cool !! This looks like a little overkill but the general idea is
really great !!

Thx Jonas !

Re: Objects or not ?

floortje4@gmail.com wrote:
> On 13 nov, 14:40, Jerry Stuckle wrote:
>
> Hi Jerry,
>
>> First of all, don't do the select in your code. Let your objects do it.
>
> Yup just trying to make the point without producing tons of code :-)
>
>> In this case, create a userlist class and let it perform the select
>> statement, building a new userobject for each row.
>
> Maybe I dont understand you but is what im trying to avoid. Lets say
> $aData contains 1000 rows with unique UserId's. Then this code would
> produce 1001 select queries.
>

But what you should be avoiding is having to worry about stuff like this
in your code. OO programming is all about abstracting the details.

> function CreateUserObj()
> {
> $aData=$db::select('SELECT UserId FROM forum');
>
> foreach ($aData as $val)
> {
> // executes a new select statement
> $aUserObj[$val['UserId']]=new User($val['UserId']);
> }
>
> return $aUserObj;
> }
>
>

No, this is one query, and you retrieve multiple rows from that query.

But if you need 1000 rows, you need to retrieve all 1000 rows somehow.


--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

Re: Objects or not ?

On 13 nov, 15:13, Jerry Stuckle wrote:

> >> In this case, create a userlist class and let it perform the select
> >> statement, building a new userobject for each row.

After re-reading your reply im guessing we are not talking about the
same thing. Im talking about a join of 2 tables: users and
forum(entries). Im not quite sure where the userlist fits in. I have
allready performed the select statement joing the two tables and I
have all the data I need. Ater getting all the data I need I would
like to make use of the handy classes I have created. Are you saying
that I should pass specific data from each row to 2 new objects (class
User and class Forum).

Arjen

Re: Objects or not ?

On Nov 13, 8:23 am, floort...@gmail.com wrote:
> Hi,
>
> Im having a discussion with a friend about Objects.
>
> Let say I create a user Object
>
> class User
> {
> private $_aUserdata;
> rivate $_sId;
>
> function __construct($id)
> {
> $this->_sId=$id;
> $this->_aUserdata= db::select('SELECT * FROM users WHERE UserId ="'.
> $id.'"');
>
> }
>
> public function getName()
> {
> return $this->_aUserdata['firstnamename'].' '.$this-
>
> >_aUserdata['lastname'];
> }
>
> function __destruct()
> {
> // just for this example
> echo 'UPDATING USER';
> $db::update('UPDATE users SET' lastsused="NOW()" WHERE UserId="'.$this-
>
> >_sId.'"' );
> }
> }
>
> Now i can have easy access to the users
>
> $user=new User(1);
> echo $user->getName();
>
> // Arjen
> // UPDATING USER
>
> But no script I ever write is this simple.
> Lets says that I want to select all forum entries and display the user
> name along with the other data
>
> $forumdata=$db::select('SELECT * FROM forum INNER JOIN USERS on
> forum.UserId=users.UserId');
>
> Now my userclass is completely useless because I allready have all the
> data I need and I dont want to do another xxx select queries to the
> user database. However i would still like to use User::getName()
> because I might do some fancy calculation there and i dont want to
> multpily my code. I now also dont have access to (the complpetely
> useless) destructor so I have to update this manually.
>
> How would I go and solve such a problem ?
>
> I could imagine that I could loop through the forumdata and load the
> user data into a new user object but is that really a good
> solution ?
>
> Arjen

There are lot's of different ways to do this. I typically create
static "factory" methods to create the objects rather than call the
constructor directly. For instance, your constructor can look like
this:

//Protected so you have to use the factory methods
protected function __construct($id, array $userData) {
$this->_sId = $id;
$this->_aUserdata = $userData;
}

Now you create a factory method called "fromID" like this:

public static function fromID($id) {
$class = __CLASS__;
$u = new $class($id, db::select('SELECT * FROM users WHERE UserId
="'.$id.'"'));
return $u;
}

And you can create a factory method called "fromArray" like this:

public static function fromArray(array $a) {
$class = __CLASS__;

$r = array();
foreach($a as $row)
$r[] = new $class($row['id'], $row);

return $r;
}

So, for a single id you can get your object like this:

$user = User::fromID(42);

And, if you already have the result of a query in an array, you can
get an array of user objects without re-running your query like this:

$forumdata = $db::select('SELECT * FROM forum INNER JOIN USERS on
forum.UserId=users.UserId');
$users = User::fromArray($forumdata);

Re: Objects or not ?

floortje4@gmail.com wrote:
> On 13 nov, 15:13, Jerry Stuckle wrote:
>
>>>> In this case, create a userlist class and let it perform the select
>>>> statement, building a new userobject for each row.
>
> After re-reading your reply im guessing we are not talking about the
> same thing. Im talking about a join of 2 tables: users and
> forum(entries). Im not quite sure where the userlist fits in. I have
> allready performed the select statement joing the two tables and I
> have all the data I need. Ater getting all the data I need I would
> like to make use of the handy classes I have created. Are you saying
> that I should pass specific data from each row to 2 new objects (class
> User and class Forum).
>
> Arjen
>
>

Yes, UserList would be a list of users. It would perform the SQL
operations to fetch the information and then create a new User object
for each user returned.

And if one User could have many Forum entries, the User class should
contain a list of ForumEntry class objects. The UserList object would
handle this, also (in conjunction with the User object).

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

Re: Objects or not ?

floortje4@gmail.com wrote:
> On 13 nov, 15:13, Jerry Stuckle wrote:
>
>>>> In this case, create a userlist class and let it perform the select
>>>> statement, building a new userobject for each row.
>
> After re-reading your reply im guessing we are not talking about the
> same thing. Im talking about a join of 2 tables: users and
> forum(entries). Im not quite sure where the userlist fits in. I have
> allready performed the select statement joing the two tables and I
> have all the data I need. Ater getting all the data I need I would
> like to make use of the handy classes I have created. Are you saying
> that I should pass specific data from each row to 2 new objects (class
> User and class Forum).
>
> Arjen
>
>

As an example:

class User {
private $userId;

function __construct($userId = null) { // To allow for a new user
$this->userId = $userId;
}

function getUserId() {
return $this->userId;
}

function setUserId($userId) {
// Validate it as necessary
// You can also return true/false depending on if
// validation succeeds or fails
$this->userId = $userId;
}

// ... other functions
}

class UserList {
private $users;

function __construct () { // Initialize the array
$users = array();
}

function fetchForumUsers($db) {
$userIds=$db::select('SELECT UserId FROM forum');
foreach ($userIds as $userId) {
// This does NOT execute a new SELECT statement!
$this->users[]=new User($userId);
}

function fecthUsers() {
return $this->users;
}
// ... other functions
// I often also add first(), last(), next() and prev() functions here


}

$userList = new UserList();
$userList->fetchForumUsers();
$users = $userList->fetchUsers();


--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================