passing variables between functions

mrbean · April 16, 2011

I have a little problem.

I have made a script(function) to connect to the database.

this is the script:

connect(php)

<?php
$server = "localhost";
$username = "username";
$password = "password";

function connectdatabase($type,$database)
{
    if($type == "mysql")
    {
    $mysql = mysql_connect($server, $username, $password);
    mysql_select_db($database, $mysql);
    }
    else if($type == "mysqli")
    {
    $mysqli = new mysqli($server, $username, $password, $database);
    }
    else if($type == "mssql")
    {
    $mssql = mssql_connect($server, $username, $password);
    mssql_select_db($database, $mssql);
    }
    function query($query)
    {
        if($type == "mysql")
        {
        mysql_query($query);
        }
        else if($type == "mysqli")
        {
        $mysqli->query($query);
        }
        else if($type == "mssql")
        {
        mssql_query($query);
        }
    }
}
?>

and

aanmelden(php)

<?php
include("config.php");
connectdatabase("mysql", "[ledensysteem]");   //example
if(!empty($_POST))
{
    if(!preg_match('/^[A-Za-z1-9-]{'.$Minimale_Gebruikersnaam_Karakters.',}$/', $_POST['gebruikersnaam']))
    {
    if(!isset($error)){ $error=1;}else{$error=$error+1;}
    echo "Je gebruikersnaam moet minimaal {$Minimale_Gebruikersnaam_Karakters} tekens bevaten en mag geen komma of andere onbedoelde tekens zijn<br>Toegestaan is  <br>A t/m Z <br>a t/m z <br>1 t/m 9 <br>en -";
    }
    else
    {
    echo "geldige gebruikersnaam(goedgekeurd)";
    }
    
    if(preg_match('/^[A-Za-z1-9-]{'.$Minimale_Wachtwoord_Karakters.',}$/', $_POST['wachtwoord']) && preg_match('/^[A-Za-z1-9-]{'.$Minimale_Wachtwoord_Karakters.',}$/', $_POST['herhaalwachtwoord']))
    {
        if($_POST['wachtwoord'] != $_POST['herhaalwachtwoord'])
        {
        if(!isset($error)){ $error=1;}else{$error=$error+1;}
        echo "niet hetzelfde wachtwoord";
        }
        /*else
        {
        echo "hetzelfde wachtwoord (goedgekeurd)";
        }*/
    }
    else
    {
    if(!isset($error)){ $error=1;}else{$error=$error+1;}
    echo "wachtwoord moet minimaal {$Minimale_Wachtwoord_Karakters} tekens bevatten!";
    }
    if(!preg_match("/^[A-Za-z1-9_.-]{1,}@[A-Za-z1-9-]{1,}\.[A-Za-z1-9]{2,3}$/", $_POST['email']))
    {
    if(!isset($error)){ $error=1;}else{$error=$error+1;}
    echo "onjuiste email";
    }
    else
    {
    echo "goedgekeurd!";
    }
    if(!isset($error)) // this problem is fixed yesterday on phpfreaks.com forum!
    {
    echo "goedgedaan geen errors!";
    query("SELECT username FROM phpfreaks WHERE password = private"); // example
    }
}
else
{
?>
<HTML>
<HEAD>
<TITLE>New Document</TITLE>
</HEAD>
<BODY>
<form method="post">
<input type="text" name="gebruikersnaam" value="gebruikersnaam" maxlength="20" size="20">
<input type="password" name="wachtwoord" value="wachtwoord" maxlength="20" size="20">
<input type="password" name="herhaalwachtwoord" value="herhaalwachtwoord" maxlength="20" size="20">
<input type="text" name="email" value="voorbeeld@domeinnaam.extensie" maxlength="50" size="20">
<input type="submit" name="login" value="inloggen">
</form>
</BODY>
</HTML>
<?php
}
?>

the problem is, is that i want to pass a variable between functions like $type (the database type) between connectdatabase(); and query();

in the 'aanmelden.php' file is an example of how i use the function (on line 3 and 45 the ones with //example comment)

thanks for reading. please help.

ps. config.php contains include("connect.php");

cyberRobot · April 16, 2011

In aanmelden.php, you could assign the type to a variable ($type for example). Then pass it to both functions.

<?php
...

$type = 'mysql';
connectdatabase($type, "[ledensysteem]");

...

query($type, "SELECT username FROM phpfreaks WHERE password = private");

...
?>

Of course you'll need to modify the query function to accept the second argument.

mrbean · April 16, 2011

can i do this:

function a($type, $databasename)
{
$querytype = $type;
function b($query)
{
echo $querytype;
}
}

a(mysql, [ledensysteem]);
b(select a from b where c = c);

in example

cyberRobot · April 16, 2011

You could always try it out. I would imagine that it's not going to work; but I'm not positive on that. You may want to review the PHP manual for Variable Scope:

http://php.net/manual/en/language.variables.scope.php

mrbean · April 16, 2011

so

$querytype

must be:

global $querytype ?

gizmola · April 16, 2011

I'd suggest you have your connectdatabase() function return an array:

array('type' = $type, $dbh =  //database handle );

The trick with resource variables is that you need to pass them by reference rather than value, so you'd need to return this array by reference.

$con = array();

$con['type'] = $type;

//.... make connection and assign

$con['dbh'] = mysql_connect($server, $username, $password);
//
// At the end return $con.

return &$con;

For your query function(s) specify that the $con array will be passed by reference as well.

function query(&$con) {

}

FWIW, this is a good argument for why PHP Oop can be helpful, and in particular having a singleton registry object is a helpful design pattern.

mrbean · April 16, 2011

I have edited my script.

Result:

<?php
function connectdatabase($type,$database)
{
    $server = "localhost";
    $username = "pjzlbina_test";
    $password = "test";
    global $querytype;
    $querytype = $type;
    if($type == "mysql")
    {
    $mysql = mysql_connect($server, $username, $password);
    mysql_select_db($database, $mysql);
    }
    else if($type == "mysqli")
    {
    $mysqli = new mysqli($server, $username, $password, $database);
    }
    else if($type == "mssql")
    {
    $mssql = mssql_connect($server, $username, $password);
    mssql_select_db($database, $mssql);
    }
    function query($query)
    {
        if($querytype == "mysql")
        {
        $test = mysql_query($query);
        echo "query{$report}";
        }
        else if($querytype == "mysqli")
        {
        $mysqli->query($query);
        }
        else if($querytype == "mssql")
        {
        mssql_query($query);
        }
    }
}
?>

and i have tested it with:

<?php
include("connect.php");
connectdatabase("mysql", "[ledensysteem]");
query("select email from [gebruikers] where id = 1");
?>

It doesn't return something?

@gizmola

can u translate this:

FWIW, this is a good argument for why PHP Oop can be helpful, and in particular having a singleton registry object is a helpful design pattern.

In an easy language and with no typo?

i don't understand the words:

FWIW, Singleton and design pattern.

Sorry my english is bad.

ignace · April 17, 2011

FWIW = For What It's Worth

Design Pattern = A solution to a known problem

Singleton = A design pattern, problem: Only one instance of a certain object can exist at any given time.

Registry = A design pattern, problem: You need access to an object but you can't access it directly. For example you need the orders of a customer but you don't have the customer object (but through the Customer object you can retrieve the Orders). So, instead of calling/using a global variable you use a global access point to retrieve the instance.

$customer = Registry::get('Customer');

Internally this will do something like:

return self::getInstance()->offsetGet('Customer');

self::getInstance() returns the Singleton object.

If English is too hard for you, you can also PM me in Dutch.

mrbean · April 17, 2011

SOLVED

answer in programming language:

connect(php)

<?php
    $server = "localhost";
    $username = "pjzlbina_test";
    $password = "test";
function connectdatabase($type, $database)
{
    global $server,$username,$password,$querytype;
    if($type == "mysql")
    {
    $mysql = mysql_connect($server, $username, $password);
    mysql_select_db($database, $mysql);
    }
    $querytype = $type; //AT FUNCTION 1

    function query($query, $resulttype = "") //$resulttype = "" makes it optional to fill in.
    {
        global $queryresult,$querytype; // LOOK ITS NOW HERE  A FRIEND HELPED ME OUT 
        if($querytype == "mysql")
        {
            $query = mysql_query($query) or die('niet '.mysql_error().'');
        if($resulttype == "object")
            {
                $queryresult = mysql_fetch_object($query);
            }
        }
    }
}
?>

test(php)

<?php
include("connect.php");
connectdatabase("mysql", "pjzlbina_test");
query("SELECT * FROM `[gebruikers]` WHERE id = 1", "object");
echo "email is: {$queryresult->email}";
$load = microtime();
print (number_format($load,5));
?>

KevinM1 · April 17, 2011

Don't use 'global' to pass parameters into your functions. Pass them through the argument list. That's why it's there.

mrbean · April 18, 2011

can u please give me an example on how to use it?

KevinM1 · April 18, 2011

function connectdatabase($server, $username, $password, $querytype, $type, $database)
{
   // function code
}

Also, your function definition for query() shouldn't be placed within an if-conditional. Chances are, you want to invoke the function based on the if condition, not simply define the function.

mrbean · April 18, 2011

I dont want to re-type an variable if i use it on a function before.

And what else can i use in place of if-condition?

ternary operator?

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passing variables between functions

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