Storing database resource links

[Ney André de Mello Zunino]

Hello.

Could anyone explain to me why the following code fails?

// =====Begin sample code=====

global $blog;

define("dbHost", "localhost");
define("dbUser", "ney");
define("dbPassword", "xxx");
define("dbDatabase", "blog");

function dbConnect()
{
// Stores the database resource link in the global array
$blog["db"] = mysql_connect(constant("dbHost"),
constant("dbUser"),
constant("dbPassword"))
or die("DB connection error: " . mysql_error());
mysql_select_db('blog')
or die("Error selecting blog database: " . mysql_error());
}

function dbDisconnect()
{
// Closes the connection represented by the resource link stored
// in the global array
mysql_close($blog["db"]);
}

dbConnect();
..
..
..
dbDisconnect();

// =====End sample code=====

Upon runtime, PHP produces the following warning:

Warning: mysql_close(): supplied argument is not a valid MySQL-Link
resource in /home/ney/Blog/db.php on line 22

I would appreciate if anyone could point out my mistake and kindly
explain the situation.

Thank you.

--
Ney André de Mello Zunino

[ZeldorBlat]

Ney André de Mello Zunino wrote:

Hello.

Could anyone explain to me why the following code fails?

// =====Begin sample code=====

global $blog;

define("dbHost", "localhost");
define("dbUser", "ney");
define("dbPassword", "xxx");
define("dbDatabase", "blog");

function dbConnect()
{
// Stores the database resource link in the global array
$blog["db"] = mysql_connect(constant("dbHost"),
constant("dbUser"),
constant("dbPassword"))
or die("DB connection error: " . mysql_error());
mysql_select_db('blog')
or die("Error selecting blog database: " . mysql_error());
}

function dbDisconnect()
{
// Closes the connection represented by the resource link stored
// in the global array
mysql_close($blog["db"]);
}

dbConnect();
.
.
.
dbDisconnect();

// =====End sample code=====

Upon runtime, PHP produces the following warning:

Warning: mysql_close(): supplied argument is not a valid MySQL-Link
resource in /home/ney/Blog/db.php on line 22

I would appreciate if anyone could point out my mistake and kindly
explain the situation.

Thank you.

--
Ney André de Mello Zunino

You need to put global $blog; inside your functions. This tells PHP to
"bind" the variable $blog inside the function to the global one.
Adding that should fix it...although personally I prefer not to use
globals.

[Ney André de Mello Zunino]

ZeldorBlat wrote:

You need to put global $blog; inside your functions. This tells PHP to
"bind" the variable $blog inside the function to the global one.
Adding that should fix it...although personally I prefer not to use
globals.

Thanks for your quick reply. You are right: globals are evil, at least
most of the time. I reworked the code, which now looks like:

// =====Begin sample code=====

function dbConnect()
{
$conn = mysql_connect(constant("dbHost"),
constant("dbUser"),
constant("dbPassword"))
or die("DB connection error: " . mysql_error());
mysql_select_db('blog')
or die("Error selecting blog database: " . mysql_error());
return $conn;
}

function dbDisconnect($conn)
{
mysql_close($conn);
}

$blog["dbconn"] = dbConnect();
..
..
..
dbDisconnect($blog["dbconn"]);

// =====End sample code=====

I guess it has improved a bit, hasn't it?

Cheers!

--
Ney André de Mello Zunino

[ZeldorBlat]

Ney André de Mello Zunino wrote:

ZeldorBlat wrote:

You need to put global $blog; inside your functions. This tells PHP to
"bind" the variable $blog inside the function to the global one.
Adding that should fix it...although personally I prefer not to use
globals.

Thanks for your quick reply. You are right: globals are evil, at least
most of the time. I reworked the code, which now looks like:

// =====Begin sample code=====

function dbConnect()
{
$conn = mysql_connect(constant("dbHost"),
constant("dbUser"),
constant("dbPassword"))
or die("DB connection error: " . mysql_error());
mysql_select_db('blog')
or die("Error selecting blog database: " . mysql_error());
return $conn;
}

function dbDisconnect($conn)
{
mysql_close($conn);
}

$blog["dbconn"] = dbConnect();
.
.
.
dbDisconnect($blog["dbconn"]);

// =====End sample code=====

I guess it has improved a bit, hasn't it?

Cheers!

--
Ney André de Mello Zunino

Yes -- much better :)