Basic PDO commands to access and manipulate MySQL database

Ok. Now that we have PDO and sakila sample database installed we can begin writing our first code of accesing and showing database data.

Open Netbeans and open the HelloWorldPHP project that we hava in early posts created. Open the index.php file in the editor. Now we need to create connection to MySQL if we want to use the sakila database.

first we write try, catch block and write out our connection strings:


$hostname = "localhost";
$usernameMySQL = "root";
$passwordMySQL = "root";


try{
     ////connection code
}catch(PDOException $exp){
     /////exception code
}

In my case username and pass to MySQL are root, root
Ok so the connection code would be this:

$pdo = new PDO("mysql:host=$hostname;dbname=sakila", $usernameMySQL, $passwordMySQL);
echo "I have succesfully connected to database";

We create $pdo object which gets three parameters: name of the host and type of database driver. In my case that is localhost and mysql. So it can be other host name if the database is hosted on remote server. For dbname we write sakila the name of our db.

The exception code would be this:

 echo $exp->getMessage();

Exception code writes the error message that was took when error occured while connecting.Try, catch block is useful in cases we want to redirect the user to an error page when some error occurs, in our case we would make error page and write some text in it to notify user that there is a problem. So now my index page looks lie this:
            
$hostname = "localhost";
$usernameMySQL = "root";
$passwordMySQL = "root";
         
try{
            $pdo = new PDO("mysql:host=$hostname;dbname=sakila", $usernameMySQL, $passwordMySQL);     
       echo "I have succesfully connected to database";
}catch(PDOException $exp){           
       echo $exp->getMessage();
}
         
Now that we have successfully connected to MySQL we need to prepare some SQL statements in order to use sakila db data. 

In the try block below the echo statement write this code:

$sql="select title from film";
$stmt=$pdo->prepare($sql);
$stmt->execute();
$filmTitles=$stmt->fetchAll();

We are creating sql statement to select only the title column of the film table.
After that we prepare the sql and return the result to the $stmt variable, short for statement.
Than we execute the sql on to the database.
In the last command we fetch  all table entries that the sql statement returns and put them in array $filmTitles

Below the code for the sql write this code for printing the fetched data:

echo "<table border='1'>";
echo "<tr><td>Film Title</td></tr>";
for ($i=0;$i<sizeof($filmTitles);$i++){
                echo "<tr><td>".($i+1).". ".$filmTitles[$i]['title']."</td></tr>";
}
echo "</table>";

No we parse trought the fetched data with for cycle. $filmTitles is an array of arrays with two elements i.e it is 1000x2 matrix. So we access each element with this code $filmTitles[$i]['title'] and we can see that the subarrays are associative. You can use print_r function to print the data in filmTitles and see whats behind the hood.


Try this in your php code after the for

print_r($filmTitles); 

 This is the basic setup for PDO data access to database. More tuts on this to come :)