Using a Resource as a Class Property

[Sanders Kaufman]

I'm wondering if I'm doing this right, as far as using another class
object as a PHP class property.

class my_baseclass {
var $Database;
var $ErrorMessage;
var $TableName;
var $RecordSet;
function my_baseclass(){
$this->TableName = "";
$this->RecordSet = array();
$this->Database = new my_database();
$this->ErrorMessage = $this->Database->ErrorMessage ;
return true;
}
}

It seems to be working, but this kinds stuff skirts the edge of my PHP
grok, so I dunno.

[Michael Fesser]

..oO(Sanders Kaufman)

>I'm wondering if I'm doing this right, as far as using another class
object as a PHP class property.

class my_baseclass {
var $Database;
var $ErrorMessage;
var $TableName;
var $RecordSet;
function my_baseclass(){
$this->TableName = "";
$this->RecordSet = array();
$this->Database = new my_database();
$this->ErrorMessage = $this->Database->ErrorMessage ;
return true;
}
}

It seems to be working, but this kinds stuff skirts the edge of my PHP
grok, so I dunno.

Using one object "inside" another is called an aggregation and a very
common and important concept in OOP.

But if you want to dive into that, I would strongly recommend to upgrade
to PHP 5 and make use of its OOP features.

Micha

[Sanders Kaufman]

Michael Fesser wrote:

.oO(Sanders Kaufman)

>I'm wondering if I'm doing this right, as far as using another class
object as a PHP class property.

class my_baseclass {
var $Database;
var $ErrorMessage;
var $TableName;
var $RecordSet;
function my_baseclass(){
$this->TableName = "";
$this->RecordSet = array();
$this->Database = new my_database();
$this->ErrorMessage = $this->Database->ErrorMessage ;
return true;
}
}

It seems to be working, but this kinds stuff skirts the edge of my PHP
grok, so I dunno.

Using one object "inside" another is called an aggregation and a very
common and important concept in OOP.

So I'm doing it right?! Cool. I know there are some cases where you're
supposed to serialize objects instead of... what am I doing, passing by
reference? Instantiating?

But if you want to dive into that, I would strongly recommend to upgrade
to PHP 5 and make use of its OOP features.

I soooooo want to do this in 5... but that won't be an option until like
October. Until then, it's gotta work on 4.

[Michael Fesser]

..oO(Sanders Kaufman)

>So I'm doing it right?! Cool.

It always depends on what you want to achieve. From just looking at the
posted snippet and without knowing what the my_baseclass is supposed to
do, it's hard to tell whether you're doing it right or not, since the
code is not doing anything useful, except for initializing some member
variables.

>I know there are some cases where you're
supposed to serialize objects instead of... what am I doing, passing by
reference? Instantiating?

Aggregating. ;) You create an instance of a class, which is used inside
another object. That's it (in this case).

Serializing can be used if you want to store an object to a file or a
database.

Micha

[Sanders Kaufman]

Sanders Kaufman wrote:

function CreateTable($sT ableName, $sTableDef){
//Returns true, or false with an ErrorMessage.
//Prefixes table name and appends ISAM engine type.
//Auto-creates id field, but user should still provide a unique
field
$bRetVal = true;
$this->RecordSQL = "CREATE TABLE {$this->TablePrefix}_$ sTableName
(id INT NOT NULL AUTO_INCREMENT, PRIMARY KEY (id),
$sTableDef) ENGINE=MyISAM";
if(!$this->RunSQL($this->RecordSQL)){
$bRetVal = false;
$this->ErrorMessage=m ysql_error();
} else {
$this->ErrorMessage=" OK";
}
return $bRetVal;
}

This is actually one of the parts of my architecture I'm most proud of.
By specifying a table prefix in the class, it allows multiple web
applications to all use the same database, without any problem with same
names.

For example, suppose you use this framework to build a discussion forum
program. A client then uses it to build to web sites that use the same
database server (e.g. kaiser.kaufman. net and caesar.kaufman. net, both
using mysql.kaufman.n et).

If the discussion forum uses a "users" table, then the developer can
isolate one from the other by specifying a unite table prefix.

[Toby A Inkster]

Sanders Kaufman wrote:

class bvckvs_database

You seem to have re-invented PDO/MDB2.

http://en.wikipedia.org/wiki/Reinventing_the_wheel

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.12-12mdksmp, up 31 days, 5:12.]

Parsing an HTML Table with PEAR's XML_HTTPSax3
http://tobyinkster.co.uk/blog/2007/0...table-parsing/

[Toby A Inkster]

Sanders Kaufman wrote:

If the discussion forum uses a "users" table, then the developer can
isolate one from the other by specifying a unite table prefix.

Yep -- it's a fairly common construct. It's arguably better to use
schemas, but not all RDBMSs have very good support for that.

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.12-12mdksmp, up 31 days, 5:16.]

Parsing an HTML Table with PEAR's XML_HTTPSax3
http://tobyinkster.co.uk/blog/2007/0...table-parsing/

[Sanders Kaufman]

Toby A Inkster wrote:

Sanders Kaufman wrote:

>class bvckvs_database

You seem to have re-invented PDO/MDB2.

http://en.wikipedia.org/wiki/Reinventing_the_wheel

They say that everything that will ever be written, has already been
written.

[Sanders Kaufman]

Toby A Inkster wrote:

Sanders Kaufman wrote:

>If the discussion forum uses a "users" table, then the developer can
isolate one from the other by specifying a unite table prefix.

Yep -- it's a fairly common construct. It's arguably better to use
schemas, but not all RDBMSs have very good support for that.

Really? Common, eh? I guess I should shelve my ideas for velcro and
the frisbee, as well.

But yeah - DBMS portability was a core design concept.

[Sanders Kaufman]

Michael Fesser wrote:

.oO(Sanders Kaufman)

class my_childclass extends my_baseclass {
function my_childclass() {
// first call parent constructor or we won't have a database ...
parent::my_base class();
// then do some other stuff
...

OK - that seems to be where I went wrong. I thought the base class's
constructor was automatically called when the extended class's was.

So, bottom line, what you're saying here is that when you extend a base
class like this, you still have to manually call the base class's
constructor? Zat right?