Connecting to MySQL

The goal of this script is simply to connect to MySQL, running on your machine (localhost).

Open a new file in your text editor and start a PHP block:
```
<?
```
Create a variable to hold the result of the mysql_connect() function:
```
$connection = mysql_connect("localhost", "spike", "9sj7En4")
```
Note
The mysql_connect() function requires a host name, username, and password (in that order).
Add a die() function to the mysql_connect() line to cause the script to end and a message to be displayed if the connection fails. Within the die() function, use the mysql_error() function. The message that is printed upon error is the exact error as sent by MySQL. The new line should read as follows:
```
$connection = mysql_connect("localhost", "spike", "9sj7En4")
     or die(mysql_error());
```
Test the value of $connection. If it's true, the connection to MySQL was made, and a variable is created to hold a message:
```
if ($connection) {
     $msg = "success!";
}
```
Note
If a connection cannot be made, the script will end with the die() function.

Close your PHP block, and then add HTML:

?>
<HTML>
<HEAD>
<TITLE>MySQL Connection</TITLE>
</HEAD>
<BODY>

Print the message string:
```
<? echo "$msg"; ?>
```
Add some more HTML so that the document is valid:
```
</BODY>
</HTML>
```
Save the file with the name db_connect.php, and place this file in the document root of your web server.
Open your web browser and type http://127.0.0.1/db_connect.php.

If you entered the correct username and password, you should have a successful result.

Breaking Your Connection Script

Anytime you work with databases, you will have errors. It's inevitable. That's why I want to show you some common errors and how to handle them fairly gracefully.

You'll make a modification to the db_connect.php script that causes it to fail on connection, simply by changing the username.

Change the username to buffy (unless buffy is a real user!) so that the connection line reads as follows:
```
$connection = mysql_connect("localhost", "buffy", "9sj7En4")
     or die(mysql_error());
```
Save the file, and then open your web browser to http://127.0.01/db_connect.php.

That is some kind of nasty response! At least it tells you exactly what is wrong, and several times over: user buffy couldn't connect to MySQL. You can suppress one of the ugly warnings and just go with the message from the die() function by placing a @ before the mysql_connect() function name. Try it.

Add a @ before the mysql_connect() function, keeping the bad username:

$connection =
@mysql_connect("localhost",
"buffy", "9sj7En4")
     or die(mysql_error());

Save the file, and then open your web browser to http://127.0.0.1/db_connect.php.

With this change, the warning is suppressed, and only the message from the die() function is displayed. This is a meaningful error message output from the mysql_error() function.

If you can keep nasty errors and warnings to a minimum, it will make the overall user experience much more pleasant if your database decides to render itself unavailable during peak web-surfing hours.