Tutorial: Moving from MySQL to ADODB

		You say eether and I say eyether, 
		You say neether and I say nyther; 
		Eether, eyether, neether, nyther - 
		Let's call the whole thing off ! 


		You like potato and I like po-tah-to, 
		You like tomato and I like to-mah-to; 
		Potato, po-tah-to, tomato, to-mah-to - 
		Let's call the whole thing off ! 

I love this song, especially the version with Louis Armstrong and Ella singing duet. It is all about how hard it is for two people in love to be compatible with each other. It's about compromise and finding a common ground, and that's what this article is all about.

PHP is all about creating dynamic web-sites with the least fuss and the most fun. To create these websites we need to use databases to retrieve login information, to splash dynamic news onto the web page and store forum postings. So let's say we were using the popular MySQL database for this. Your company has done such a fantastic job that the Web site is more popular than your wildest dreams. You find that MySQL cannot scale to handle the workload; time to switch databases.

Unfortunately in PHP every database is accessed slightly differently. To connect to MySQL, you would use mysql_connect(); when you decide to upgrade to Oracle or Microsoft SQL Server, you would use ocilogon() or mssql_connect() respectively. What is worse is that the parameters you use for the different connect functions are different also.. One database says po-tato, the other database says pota-to. Oh-oh.

Let's NOT call the whole thing off

A database wrapper library such as ADODB comes in handy when you need to ensure portability. It provides you with a common API to communicate with any supported database so you don't have to call things off.

ADODB stands for Active Data Objects DataBase (sorry computer guys are sometimes not very original). ADODB currently supports MySQL, PostgreSQL, Oracle, Interbase, Microsoft SQL Server, Access, FoxPro, Sybase, ODBC and ADO. You can download ADODB from http://php.weblogs.com/adodb.

MySQL Example

The most common database used with PHP is MySQL, so I guess you should be familiar with the following code. It connects to a MySQL server at localhost, database mydb, and executes an SQL select statement. The results are printed, one line per row.

$db = mysql_connect("localhost", "root", "password");
mysql_select_db("mydb",$db);
$result = mysql_query("SELECT * FROM employees",$db);
if ($result === false) die("failed"); 
while ($fields = mysql_fetch_row($result)) {
 for ($i=0, $max=sizeof($fields); $i < $max; $i++) {
		print $fields[$i].' ';
 }
 print "<br>\n";
} 

The above code has been color-coded by section. The first section is the connection phase. The second is the execution of the SQL, and the last section is displaying the fields. The while loop scans the rows of the result, while the for loop scans the fields in one row.

Here is the equivalent code in ADODB

 include("adodb.inc.php");
 $db = NewADOConnection('mysql');
 $db->Connect("localhost", "root", "password", "mydb");
 $result = $db->Execute("SELECT * FROM employees");
 if ($result === f