How to check if the MySQL connection is made???

cyanblue

Howdy, guys... 🙂

PHP newbie here trying to check if the given MySQL database exists or not so that I could return the result back to Flash MX on Windows 2000 Pro...

Here is what I want to do...
I want to see if the connection to the MySQL server has been established... Return '11' back to Flash if it fails...
See if the database exists and return '21' back to Flash if not...

I can use mysql_select_db() to see if the database exists, but I don't know what I can do with the connection to server... I don't see any return values from mysql_connect(), yet I get "Resource id #1" when I execute the script...

Is there any way I can know if the MySQL server connection exists with PHP???

Here is the script that I have used...

<?
	include ('Include.inc');

$connectionServer = @mysql_connect($DBhost,$DBuser,$DBpass) or die ("Error connecting to the server");
print($connectionServer);
$connectionDatabase = @mysql_select_db("$DBName") or die ("Error retrieving user database");
print($connectionDatabase);
mysql_close($connectionServer);
?>

Right now, I get "Resource id #1" from print($connectionServer); and "1" from print($connectionDatabase);

I see that "Resource id #1" part will be varing depending on the connection... Should I just look for "Resource id" from the result and consider the connection is made if I get that substring??? Would there be any instance where it doesn't always say that the connection has been made???

One other question regarding this line...
$connectionServer = @mysql_connect($DBhost,$DBuser,$DBpass) or die ("Error connecting to the server");

Say that the connection is not made, then I will get "Error connecting to the server" and that string will be returned and printed out... Is it correct??? Just want to make sure of it... 🙂

Appreciate any help...

Jason

br__ken

function mysql_open()
{
 if(mysql_connect("host","user","pw") or die(mysql_error()))
 {
  if(mysql_select_db("db") or die(mysql_error()))
   return 21;
  else
   return 11;
 }
}
echo mysql_open(); // just to see if its working or not..

that might work, since if the connect fails, it will terminate php-

cyanblue

Thanks, brøken... I'll try that... 🙂

michael

// db abstraction open

function sql_open()
{
global $dbi;
if($dbi = @mysql_connect("host","user","pw") )
{
if(@mysql_select_db("db"))
return 21;
else
return 11;
}
}

This makes the connection globally available. Not sure what it will be used for ...

[deleted]

the founction mysql_real_connect()
http://www.mysql.com/doc/en/mysql_real_connect.html

cyanblue

Thanks guys... Appreciate all the helps... 🙂

[deleted]

Globals: yuk!
@ signs: carefull!
real_connect: doesn't exist in PHP (yet) and has little to do with checking for connections.

<?
// Assume everything is ok
//
$bNoErrorsFound = TRUE;

// Attempt to open the connection
// Notice there is no @ before the mysql_connect function, so the error will be printed to the screen
// If you want you can add the @ to surpress the message, but then you MUST somehow
// log the error in a file or print it in a clean message,
// otherwise you will never ever find out why your script failed.
//
if(!$connection = mysql_connect("host","user","pw"))
{
// optional error message here, log this to a file or something.
echo 'Failed to connect to database'
// Notice that there is NO EXIT or OR DIE here!
// Why would we want to terminate the app here?
// Just return some error code that the rest of the script can use to cleanly print an error and perhaps stop the script later.
$bNoErrorsFound = FALSE;
}

// Now $bNoErrorsFound contains TRUE or FALSE depending on wether the connection was made or not.
// if it was made, $connection contains it's identifier
?>