stevenclark.com.au

Carrying on from my last post about connecting to an SQL database using PHP, here are the functions I use to open and close database connections (Note: » just extends the line, you’ll need to remove that for this to work correctly).

// to open the database
function connectToDatabase ()	{
$link = mysql_connect("localhost", "database_name", »
                                  "database_password");
    if ($link && mysql_select_db("database_name"));
        return ($link);
	    return (FALSE);
}

// to close the database
function db_close($connecter)  {
    mysql_close($connecter);
}

It’s a good idea to keep these database connection functions in one place and then reuse them as you need, rather than repeating them everywhere.

Maintainability of your code is important even on smaller websites, if you only need to change a password in one place you’ll find life a lot easier. This code is very close to that found in PHP docs for mysql_connect, by the way. The connectToDatabase function returns a link identifier on success or FALSE on failure.

Further information in the mysql_connect documentation should take you an extra step as well.

So, in your PHP code where you want to run your SQL query all you need to do is something like the following snippet:

// connect to the database
include("down/in_some/folder/db_function_file.php");
$link = connectToDatabase();
    if(!link) {
        print "<p>database connection error</p>";
        mysql_close($link);
	exit();
}

Now run your query and put the values into variables, then explicitly close the link, and you’re done. Hopefully this snippet of advice might be useful.

This entry was posted on Saturday, August 23rd, 2008 at 11:49 am and is filed under php, snippets, sql. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.