Why does num_rows not work?

Simply $bruce is not an object. $dean is an object because it is the result of a class instantiation:

$dean = new Test();

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$dean is an object of the class Test.

$bruce = SqlQuery(...

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$bruce is the result of a method not an object. You need to have a method in the Test class whcih returns the nume of rows and then call it this way:

$dean = new Test();
$dean->GetNumRows($query);

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and in the Test class:

class Test {

      function GetNumRows($query){
      $bruce=SqlQuery($query);
      return $bruce->num_rows;
      }
//this code could not work depending on how is implemented in your code SqlQuery 
//function
}

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Your actual function the_query must be rewritten this way:

      
    function the_query(){
        $bruce=SqlQuery("","select * from registration where id='$_GET[id]'");
        return $bruce->result; // again, this depends on how SqlQuery function is implemented
    }

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If you want to post here your full code for class Test (SqlQuery code included) I'll be happy to help you. About Php object oriented programming, let me suggest this book (http://www.apress.com/9781590599099/): it's not so easy tor ead, but it makes you to  jump forward in php oop.

Cheers

OK, I see.

So what if I did this in my SqlQuery function (I added what I'm hoping to be a "count" property.

function SqlQuery($database,$sql){

$dbhost = "localhost";    // Your database server 192.168.0.10
$dbuser = "root";      // Your db username
$dbpass = "";      // Your db password
$dbname = "Showdown";      // Your database name

$dbc = new mysqli($dbhost, $dbuser, $dbpass, $dbname);

$query_results = mysqli_query($dbc,$sql);
$row = mysqli_fetch_assoc($query_results);
$count=mysqli_num_rows($query_results);
return $row;
return $count;

}

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Does that solve the problem of the count not being a property of the dataset? I want to think that I'm on to something but now I don't know how to retrieve it.

When I try return $bruce[count] I get an error.

Ahh, I'm close, but I'm still missing it.

Sorry guys, there was some posting going on while I was making my way through this. Here's the whole code, top to bottom just so I'm doing everybody the courtesy of letting them see the whole mess and not just a puddle...

songwriting_class.php...

function SqlQuery($database,$sql){

$dbhost = "localhost";    // Your database server 192.168.0.10
$dbuser = "root";      // Your db username
$dbpass = "";      // Your db password
$dbname = "Showdown";      // Your database name

$dbc = new mysqli($dbhost, $dbuser, $dbpass, $dbname);

$query_results = mysqli_query($dbc,$sql);
$row = mysqli_fetch_assoc($query_results);
$count=mysqli_num_rows($query_results);
return $row;
return $count;

}

class Test {

	function the_query(){
	$bruce=SqlQuery("","select * from registration where id='$_GET[id]'");
		if($this->count==0)
		{
		echo "nope";
		}
		else
		{
		return $bruce['first_name'] ;
		}
	}
}

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... and then the page where I'm attempting to retrieve the results...

	<?php 
							require_once('classes/songwriting_class.php'); 
							$dean = new Test();
							//var_dump($dean);
							echo $dean->the_query();
							?>

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You can have Only one return statement in a function.  And it can only return One variable or object like an array.

hey, , you seem to be on the right track in setting up your code, but there are things that can help you, for instance , in your -

function SqlQuery($database,$sql){

$dbhost = "localhost";    // Your database server 192.168.0.10
$dbuser = "root";      // Your db username
$dbpass = "";      // Your db password
$dbname = "Showdown";      // Your database name

$dbc = new mysqli($dbhost, $dbuser, $dbpass, $dbname);

$query_results = mysqli_query($dbc,$sql);
$row = mysqli_fetch_assoc($query_results);
$count=mysqli_num_rows($query_results);
return $row;
return $count;

}

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you do not seem to have used something to get "Multiple" returns from a function, the most common is the Array, as is returned by many PHP functions, , as in dis code -

function SqlQuery($database,$sql){

$dbhost = "localhost";    // Your database server 192.168.0.10
$dbuser = "root";      // Your db username
$dbpass = "";      // Your db password
$dbname = "Showdown";      // Your database name

$dbc = new mysqli($dbhost, $dbuser, $dbpass, $dbname);

$query_results = mysqli_query($dbc,$sql);
$row = mysqli_fetch_assoc($query_results);
$count=mysqli_num_rows($query_results);
return array($row,  $count);

}

//used like -
$dataRe = SqlQuery($db ,$query);
echo "Returned Row Count is ".$dataRe[1];

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you may or may Not want to have an overall ObjOrein code base, if so you can also return an object wid properties

$re = new stdClass;
$re->count =  $count;
$re->row =  $row;
return $re;
// or in one line -
//return (object) array('count' => $count, 'row' => $row);
// = = = = =

//used like -
$dataRe = SqlQuery($db ,$query);
echo "Returned Row Count is ".$dataRe->count;

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you may try and consider the Class you write, as a code location for ALL the Database Code you use for the song stuff, a code container for all data base values and functions, if you look for song database code, you will know it's in that Class.

Slick, Dave, Ray, Marcus - y'all rock, it's just that simple.

Here's what you've explained thus far and I want to explain it back to you just to make sure I understand "why" as well as "what."

Marcus, I like your paradigm and between you and Dave I understand now that, unlike a procedural approach (which I've been doing since before 2008) where I would often preface the mysqli_fetch_assoc with a mysqli_num_rows and make sure there was data in the recordset before I attempted to retrieve it, there now has to be a separate function to see how many rows there are in the database.

Got it.

Marcus, I understand the logic of everything you've written save line 12 of the DBManager class. Tell me if I'm understanding this correctly: You begin by declaring your variables and then, using your construct function, assign values to those variables, which would actually be referred to as "properties" in that they're occurring within a class. But at line 12, you're not assigning a value. Rather it appears that you're saying programmatically that all of the properties that you've defined within your construct function are now being cumulatively represented by "dbconnect." I'm thinking that "dbconnect" will now be recognized as the collection of properties you've defined in the construct function every time that "dbconnect" is referenced within the DBManager class.

And that's going to be handy given the title of your next method which is the "dbconnect" function. Because you've prefaced this with the previous construct function, when the dbconnect function kicks into gear, it is automatically bringing to the table all of the credentials that you're going to need to login to the database and now doing so in the context of a mysqli connection.

Correct?

I'm thinking that "dbconnect" will now be recognized as the collection of properties you've defined in the construct function

More precisely, dbconnect is a method (that is a function which is part of a class) whose goal is to establish a connection to the database using as parameters the properties defined in the constuctor. You can do this even in the constructor itself and Usually I do it, since this class has no reason to exist without a database connection:

<?php
class DBManager {
	public $dbhost;
	public $dbuser;
	public $dbpass;
	public $dbname;
	public $dbc;
	public $msg;

	function __construct(){
		$this->dbhost = "localhost";    // Your database server 192.168.0.10
		$this->dbuser = "root";      // Your db username
		$this->dbpass = "cavallo";      // Your db password
		$this->dbname = "Showdown";      // Your database name
		$dbc = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
	}

	function dbconnect(){
			$dbc = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
	}
		
}

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Anyway, if you're skilled in procedural Php, I suggest to read (before the book a suggested above) this book: PHP Master Write Cutting-Edge Code It offers a good introduction to Object oriented programming in Php (plus several others interesting things) and I'm sure you'll appreciate it to help you in understanding this approach to the programming. It'll help you also to understand what is more deeply treated in the Matt Zandstra book PHP Objects, Patterns, and Practice - strongly recommended :-)

Hope this clarify your doubts

Cheers

Ooops, sorry, in the snippet above i leaved the no more used function dbconnect():

<?php
class DBManager {
	public $dbhost;
	public $dbuser;
	public $dbpass;
	public $dbname;
	public $dbc;
	public $msg;

	function __construct(){
		$this->dbhost = "localhost";    // Your database server 192.168.0.10
		$this->dbuser = "root";      // Your db username
		$this->dbpass = "cavallo";      // Your db password
		$this->dbname = "Showdown";      // Your database name
		$dbc = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
	}


}
                                            

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Note that 'num_rows' needs to be called immediately after the query and stored if necessary.  It will not be valid even if you do get a value at any other time.  It is tied to the query but is not returned with it.

Alright, I think I've got it, but I'm getting an error that says I'm not able to connect to the database.

The login credentials are correct. Do you see anything with the way that I've implemented your suggestions that would result in a bad database connection?

Here's the code:

<?php
class DBManager {
	public $dbhost;
	public $dbuser;
	public $dbpass;
	public $dbname;
	public $dbc;
	public $msg;

	function __construct(){
		$this->dbhost = "localhost";    // Your database server 192.168.0.10
		$this->dbuser = "root";      // Your db username
		$this->dbpass = "";      // Your db password
		$this->dbname = "showdown";      // Your database name
		$dbc = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
	}

	function SqlQuery($sql) {
	$query_results=mysqli_query($this->dbc, $sql);
	$row=mysqli_fetch_assoc($query_results);
	return $row;
	}
	
	function SqlNumRows($sql) {
	$query_results=mysqli_query($this->dbc, $sql);
	$count=mysqli_num_rows($query_results);
	return $count;
	}

}

class Test {

	function getUserName(){
        $dbman = new DBManager();
	$bruce = $dbman->SqlQuery("","select * from registration where id='2545'");
		if($this->count==0)
		{
		return "nope";
		}
		else
		{
		return $bruce['first_name'] ;
		}
	}
}

?>

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.and here's the error that I'm getting...


Warning: mysqli_query() expects parameter 1 to be mysqli, null given in C:\wamp\www\Showdown\adm\classes\songwriting_class.php on line 19

Warning: mysqli_fetch_assoc() expects parameter 1 to be mysqli_result, null given in C:\wamp\www\Showdown\adm\classes\songwriting_class.php on line 20

Notice: Undefined property: Test::$count in C:\wamp\www\Showdown\adm\classes\songwriting_class.php on line 37
nope

I think this may help ? Looks to me as if in marqusG class code a  $this  is missing for the class property of $dbc, as in -
$this->dbc = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);

and just for clarity, there is a difference between how the new msqli operates in OO and in it's procedure mode
I beleive the procedure mode goes like

$this->dbc = mysqli_connect($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);

$query_results = mysqli_query($this->dbc, $sql);


OO mode as -
$this->dbc = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
$query_results = $this->dbc->query($sql);

- - - - -
I really think that the advantage of Object code in php is to make the developers code work "Less" less lines of code to write, less time to do work for results. So brucegust , even though you are learning Class now, see if you can detect, how the organization and connected relation ships of the Class can make programming "Better" for your web output, for me, instead of making a million different Class functions for every little separate thing that needs to be done (as the num-Rows thing), I save time by seeing in my page output I need three or four things from DB, instead of calling 4 object methods, I have One method that returns the 4 things I need (in array or object) so I make one call.
Also in DB selects, you can do that select once, output a portion of the return Data in method1, store in array property of Class the other select return data, and in method2 you can get that class property data later, and not do another select. But a main advantage (to me) of Class is the internal property storage of needed info for that object, to be used several times in several different methods, and having  methods that can change the output and relation ship of several other class methods, , , as in there is a connection for things in a Class due to shared $this properties, that's rough to do in code outside of a class.

Hey, Slick!

I so appreciate your time and I do see the "prize" as far as mastering this and getting to the point where I'm actually writing less code.

I'm still not where I need to be with my current dilemma however. Code is attached. I'm getting the following errors:

Warning: mysqli::query() [mysqli.query]: Empty query in C:\wamp\www\Showdown\adm\classes\songwriting_class.php on line 19

Warning: mysqli_fetch_assoc() expects parameter 1 to be mysqli_result, boolean given in C:\wamp\www\Showdown\adm\classes\songwriting_class.php on line 20

Notice: Undefined property: Test::$count in C:\wamp\www\Showdown\adm\classes\songwriting_class.php on line 37

So, I'm now getting a connection, but now I'm being told I don't have a query and then my connection seems to be an issue once again in line 20.

Thoughts?

<?php
class DBManager {
	public $dbhost;
	public $dbuser;
	public $dbpass;
	public $dbname;
	public $dbc;
	public $msg;

	function __construct(){
		$this->dbhost = "localhost";    // Your database server 192.168.0.10
		$this->dbuser = "root";      // Your db username
		$this->dbpass = "";      // Your db password
		$this->dbname = "showdown";      // Your database name
		$this->dbc = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
	}

	function SqlQuery($sql) {
	$query_results = $this->dbc->query($sql);
	$row=mysqli_fetch_assoc($query_results);
	return $row;
	}
	
	function SqlNumRows($sql) {
	$query_results = $this->dbc->query($sql);
	$count=mysqli_num_rows($query_results);
	return $count;
	}

}

	class Test {

	function getUserName(){
		$dbman = new DBManager();
		$bruce = $dbman->SqlQuery("","select * from registration where id='2545'");
		if($this->count==0)
		{
		return "nope";
		}
		else
		{
		return $bruce['first_name'] ;
		}
	}
}

?>

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Oooops, Slick812 is right, I forgot a $this: I'm very sorry for this - for $this :)

@Slick812: I think you're expert enough in oop to choose to not follow basic rules of OOP programming: you know that a class has to provide 4 infos and you decide to pack all that infos in a single array returned by one method: personally, I don't like it but who am I to judge? The beautyful thing of programming is we are all lone wolfs and everyone can do what he thinks is better for him. But if you have no experience in oop maybe it is better to begin following all rules literally and then you'll can adjust your programming style as you wish: you can't run if you don't know how to walk - hope it's clear what I mean...

@brucegust: now your method SqlQuery requires only one parameter (I've deleted the one - $database - because it was unneeded since the database name is set in the class constructor): consequently, you mast call it this way:

$bruce = $dbman->SqlQuery("select * from registration where id='2545'");

instead of

$bruce = $dbman->SqlQuery("","select * from registration where id='2545'");

Sweet!

I got it all down to one last error. I'm being told...

Notice: Undefined property: Test::$count in C:\wamp\www\Showdown\adm\classes\songwriting_class.php on line 37
nope  

I understand that a property within a class is a variable, but I don't see where that is NOT being defined.

The other errors are gone, so yeah, baby! But this last thing is still alluding me.

What am I missing?

since this is for brucegust  learning, I'll give more to chew on, I HIGHLY recommend the prepare() and execute() for ALL user input in the mysqli query code.

Below is a rewrite of the above code using prepare and execute, this is more or less what's in the PHP manual, and most every tutorial. I have the exact same code for the Post verification and - new mysqli( ) -  but instead of using query( ), I use the prepare( ) , bind_param( ), execute( ), and bind_result( ) methods.


      using mysqli->prepare( ) for a SELECT query

// get user Input from page Form
$instID = $_POST['inst-ID'];// value here is 'mathSmith2' for instuctor ID
// Always verify that the POST and GET values are within acceptable limits for the DataBase
if ((strlen($instID) > 5) && // all Instuctor ID are 6 or more in length
    (strlen($instID) < 15) && // all Instuctor ID are less than 15 in length
    (preg_match('/[^a-zA-Z0-9]/', $instID) == 0)) // instID must be only Alfa Numeric
    {
// with MySLIi the database is sected in the creation
    $mysqli = new mysqli('localhost', 'user', 'password', 'eduDB');
    if (!mysqli_connect_errno())
        {
        $numRows = 0;
// In the prepare, use the ? for a PlaceHolder to Bind the Paramerts later
        $query = 'SELECT date1, time1 FROM examkit WHERE instrucID = ?';
        $stmt = $mysqli->prepare($query);// prepare returns a mysqli Statement Object
        if($stmt) {// if the SQL language in prepare is Wrong,  $stmt is false
// IMPORTANT, unlike Old and the mysqli->query( ) you should NOT escape the User Input with real_escape_string()
// because the Value of $instID is NOT used as a php string in the SQL prepare string

// you MUST assign a variable NAME to every ? in the prepare( ) SQL
            $stmt->bind_param('s', $instID); // assign $instID to the ? for SQL test 'WHERE instrucID = ?'

// whenever execute() is used, the C code underneth PHP reads the Value in the $instID variable
// and sends it to the MySQL server, where the prepare() SQL methods are actually run at that time,
// with the execute DATA in the ? positions.
// this happens without any visible code method for the php developer to see, which is strange for many using PHP
            if($stmt->execute())
               {
// IMPORTANT, after the statement execute( ), the $stmt does NOT contain any Returned Query Data
// the $stmt is ONLY a reference object to the returned Query data still on the MySQL server
// which has NOT been returned to PHP at this point.

// You get the SELECT prepare( ) Result Data by the statement->bind_result( ) for Returned Row Values
// you MUST assign a variable NAME to every column in the SELECT, here it's two as 'SELECT date1, time1'
// the variable assignment is ALWAYS the exact order in the SELECT text, one after the other, from left to right
            $stmt->bind_result($date1, $time1);
            echo 'Statement FETCH OUTPUT BELOW -<br />';
            while ($stmt->fetch()) // fetch() will place the ROW values into the Bound variables
                {
//unlike regular PHP, the $date1 and $time1 values will change without any visable code assignment
// on each while loop of fetch(), the C code underneth PHP changes the Value assignment of $date1 and $time1
                echo 'date1= ',$date1,' |time1= ',$time1,'<br />';
                ++$numRows; //a way to get the number of rows
                }
            echo '<br />Num Rows in Fetch ',$numRows,'<br />';
            } // bracket for if($stmt->execute())
            else echo 'ERROR - execute  FAILED= ',$mysqli->error,'<br />';
            $stmt->close();// release mysqli references as soon as possible
// IMPORTANT, close $stmt to release all the query Result return data still on the MySQL server
            } // bracket for if($stmt)
            else echo 'ERROR in PREPARE= ',$mysqli->error,'<br />';
        $mysqli->close(); // release mysqli references as soon as possible
        } // bracket for if (!mysqli_connect_errno())
        else echo '<b>BIG MySQL ERROR - did NOT Connect to database ', mysqli_connect_error() ,'</b>';
    } // if ((strlen($instID)
    else echo 'ERROR - instID is NOT a valid Value<br />';

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Some Differences in code operations for using execute( )
In the SELECT used above, when execute( ) is used, the returned Statement Object, does NOT have any DATA returned from the selection out of the Table, these are keep on the MySQL server untill you close the Statement Object, here I use the $stmt->bind_result( ) and do while loop with $stmt->fetch(), this gets ONE row of DATA from the MySQL pipeline on each loop, this allows you to BREAK the loop and stop, when you find the DATA you are looking for, and not have useless DATA crowd the MySQL pipeline. Although this is seldom any concern for php developers, it can be used if you know whats happening and have big DATA server slowdowns. Although not in this code example, you can transfer ALL SELECTED DATA to "php storage" through the MySQL pipeline, with the use of  $stmt->store_result(); , many in php that do not understand where and how the data is stored, often misunderstand the use of this function,

Marcus, your last suggestion did work after I changed this:

$count = $bruce->SqlNumRows("select * from registration where id='2545'");

to this...

$count=$dbman->SqlNumRows("select * from registration where id='2545'");

So, it's done! I got this piece completed and given the enormity of the information that's been disseminated in terms of theory, I'm confident I have a great headstart in terms of being able to continue building using an OOP approach.

Thanks for the help!

just for an "alternate" view, (no points please) you might look at this, it is untested and may have formatting text errors, , but hopefully it may give you a little more possiblities for Class design, , please consider that when you call -
$query_results = $this->dbc->query($sql);
this takes any $sql  string, and there are many strings that Will Not Work.

class DBManager {
// it has always helped me in debugging and use, to start CLASS development
//with ALL properties given a DEFAULT value here
	public $dbhost = "localhost";
	public $dbuser = "root";
	public $dbpass = "passw";
	public $dbname = "showdown";
	public $dbc = NULL;
	public $msg = '';

	function __construct(){
		$this->errors = array(); //You do not need to have properties 
//declared above, but it helps reading code later
// be aware that PHP Classes are dymanmic, you can add and delete public class properies at any time
// inside the class code OR in the Object - $dbman->newProperty
		$this->dbc = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
	}

	public function SqlQuery($sql) {
	if ($query_results = $mysqli->query($sql)) {
		$re = new stdClass;
		if ($query_results->num_rows < 1) {
			$re->count = 0;
			$re->row = array();// you can leave this out or have a null, 
//I like to have consistant returns so if the $re->row is expected to be an array do an array

			return $re;
			}
		$row = $query_results->fetch_array(MYSQLI_ASSOC);
		$re->count = $query_results->num_rows;
		$re->row = $row;
		return $re;
		} 
		else
		{
		$this->errors['mysqli-query'] = $mysqli->error;
		return false;
		}
	}
	
	public function SqlNumRows($sql) {
	if ($query_results = $mysqli->query($sql)) {
		return $query_results->num_rows;
		} 
		else 
		{
		$this->errors['mysqli-query'] = $mysqli->error;
		return false;
		}
	}

}

	class Test {

	public function getUserName(){
		$dbman = new DBManager();
		if($bruce = $dbman->SqlQuery("","select * from registration where id='2545'")){
		if($bruce->count==0)
		{
		return "nope";
		}
		else
		{
		return $bruce->row['first_name'] ;
		}
		} else return false;// just for errors
// to debug
//foreach($dbman->errors as $k => $v) echo ' dbmanError: ',$k,' - ', $v;
	}
}

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just give it a look, and see if anything clicks for you.