Why is not that no DB is selected

1

now, in the past few days of learning PHP, i have noticed that the way to connect to a DB (connect, select, query, etc) is usually similar to the code below… now i thought, why not make that a function, call it, and pass the variables like which DB, the query, etc…

now, i have made a code… tested it out a little but none seem to work… can i put this in a function at all?

like i just do this in the php page:

ConnectSelectDB();

$searchSt = "SELECT * FROM $PORTFOLIO_TABLE LIMIT 10";
	
		//connect to db
		if(!($link=mysql_pconnect($hostName, $userName, $password))) {
			DisplayError(sprintf("error connecting to host %s, by user %s",$hostName, $userName));
			exit();
		}
	
		//select db
		if(!mysql_select_db($databaseName, $link)){
			DisplayError(sprintf("Error in selecting %s database",$databaseName));
			DisplayError(sprintf("error: %d %s",mysql_errno($link), mysql_error($link)));
			exit();
		}
	
		//execute search for all items
		if(!($result =mysql_query($searchSt, $link))){
			DisplayError(sprintf("Error in executing %s statement", $searchSt));
			echo "<BR>rowid = $rowid<BR>";
			DisplayError(sprintf("error: %d %s", mysql_errno($link), mysql_error($link)));
			exit();
		}

some examples would be nice :slight_smile:
thank you for helping out a newbie :slight_smile:

2

common.php:


// Database details
$dbHost = "localhost";
$dbUser = "YOU"; //root
$dbPass = "password"; //""
$dbName = "myDb";

// Common functions

/*********************************************************
** Function: dbconnect()                                **
**     Desc: Perform database server connection and     **
**           database selection operations              **
*********************************************************/

function dbConnect() {
    // Access global variables
    global $dbHost;
    global $dbUser;
    global $dbPass;
    global $dbName;
    
    // Attempt to connect to database server
    $link = @mysql_connect($dbHost, $dbUser, $dbPass);

    // If connection failed...
    if (!$link) {
        // Inform Flash of error and quit
        fail("Couldn't connect to database server");
    }

    // Attempt to select our database. If failed...
    if (!@mysql_select_db($dbName)) {
        // Inform Flash of error and quit
        fail("Couldn't find database $dbName");
    }
    
    return $link;
}
function dbQueryFirst($query) {
    // Does a query and returns first row
    $result = @mysql_query($query);

	if (!$result) {
		print $query . "<br>
";
		print mysql_error() . "<br>
";
		fail("Query failed");
	}

    $returnArray = @mysql_fetch_array($result, MYSQL_ASSOC);

    @mysql_free_result($result);

    return $returnArray;
}


/*********************************************************
** Function: fail()                                     **
**   Params: $errorMsg - Custom error information       **
**     Desc: Report error information back to Flash     **
**           movie and exit the script.                 **
*********************************************************/
function fail($errorMsg) {
    // URL-Encode error message
    $errorMsg = urlencode($errorMsg);
    
    // Output error information and exit
    print "&result=Fail&errormsg=$errorMsg";
    exit;
}

to use this: in any other php:

// Load in common variables and functions
include("common.php");

// Connect to MySQL Server
$link = dbConnect();
//example
// Build query to fetch post
$post = dbQueryFirst("SELECT * FROM forumPosts WHERE postID = $postID");
// Setup our variable to hold output
$output = "&postID=$postID";

// Add post details to output
$output .= "&postMessage=" . urlencode($post['message']);
$output .= "&postNotify=" . $post['notify'];
$output .= "&postAddSig=" . $post['addsig'];

// Output all data in one go
echo $output;

// Inform Flash of success
print "&result=Okay";

// Close link to database server 
mysql_close($link);