Creating an object

[joesaddigh]

Hi,

 

I have decided to try and write some OO php.

 

I have a simple class with one function. I am trying to instantiate an object of that class using the new operator but get an error.

Parse error: syntax error, unexpected T_OBJECT_OPERATOR in C:\wamp\www\School\addcourse.php on line 38

	
<?php 
    $CDBController = new CMasterDataController; //THIS IS LINE 38
    CMasterDataController->PerformQuery("SOME SQL HERE");
?>

 

I am including the file that contains this class (CMasterDataController) in this file (addcourse.php). The version of PHP i am using is 5.3.8.

Does anybody know what I am missing?

 

Thanks,

Joe

 

[requinix]

Try changing the line below that.

$CDBController->PerformQuery("SOME SQL HERE");

[joesaddigh]

Ah yess..  What an idiot I am. I want to try and put some of the common tasks that I perform regarding DB functions into a class which I can just create and use all over the place. The thing I am finding difficult to get used to is not having to specify data types and knowing what a function like:

 

mysql_query

mysql_fetch_array

 

returns? Also when you declare a function within a class you dont say perhaps:

 

ReturnType function NameOfFunction( param1, 2, 3 )

{

    return something;

}

 

You can simply do this:

 

function NameOfFunction( param1, 2, 3 )

{

    return something;

}

 

So if I wanted to return the result of a mysql_fetch_array from a function that takes sql as a param and then use this in the caller of the func how woud I loop through the result that I would expect to be returned?

 

Thanks for your help.

[requinix]

To know what those functions return you look them up in the PHP manual. After a couple times you'll remember.

mysql_query. Returns a resource (SELECT query) or true (not a SELECT query) or false (error).

mysql_fetch_array. Returns an array (a row from the result) or false (no more rows).

 

 

PHP is loosely-typed which means you do not specify type names for variables. There is type hinting for function parameters, but that's a different (though related) thing.

If you only need to return one row from the query then make your NameOfFunction use a mysql_query() + mysql_fetch_array(), returning the result of the latter.

function QueryOne($sql) {
$result = mysql_query($sql);
if ($result) {
	return mysql_fetch_array($result);
} else {
	// error
	return $result;
}
}

If you want multiple rows then you'll need a loop.

function QueryMany($sql) {
$result = mysql_query($sql);
if ($result) {
	$results = array();
	while ($line = mysql_fetch_array($result)) $results[] = $line;
	return $results;
} else {
	// error
	return $result;
}
}

[joesaddigh]

That' excellent. Looking forward to creating some useful classes that I can re-use. One more thing if you don't mind. What do you use to debug PHP and is this easy to setup (know of any tutorials). I have tried setting up Zend studio before but not had a lot of luck so am using Dreamwever for now which means that I simply echo variable contents as and when I need to debug.

 

Sorry that this is unrelated but would appreciate any help on this.

 

Thanks again! 

[requinix]

I personally don't use any tools. Because of how PHP works it's generally easier for me to echo/die a few values here and there and re-run the script.

The classic example is dealing with SQL queries:

// complicated stuff to build a $query
echo "\n"; // inserted when $query seems wrong, removed when I figure it out
$resultset = mysql_query($query);

[joesaddigh]

Yeah that's how I have got along so far. Going to give setting up zend another go as it makes itso much quicker being able to debug. Thanks for your help.