Use Database

Let's use MySql. database. To use a database, the first thing is to connect to the database server:

$host     = "server_name"; 
$user     = "database_user";    
$password = "password"; 
$dbn      = "database_name"; 

mysql_connect($host, $user, $password) or 
  die ("Cannot connect to the database server");
mysql_select_db($dbn) or 
  die ("Cannot connect to the database");

After opne the database, we use the mysql_query funcation and a SQL query:

$q_sql = mysql_query("select * from members"); 
while ($rs=mysql_fetch_row($q_sql)) {
 ... 
}

Usually, this function is used with mysql_fetch_row or mysql_fetch_array to get the result of the SQL query row after row in an array:

$q_sql = mysql_query("select * from members"); 
while ($rs=mysql_fetch_row($q_sql)) { 
$lastName = $rs[3]; 
$firstName = $rs[4]; 
echo $lastName . ", " . $firstName;
}

Or:

$q_sql = mysql_query("select * from members"); 
while ($rs=mysql_fetch_array($q_sql)) { 
$lastName = $rs["lastName"]; 
$firstName = $rs["firstName"]; 
echo $lastName . ", " . $firstName;
}

When we have finished to use the database, we should close the connection with the server:

mysql_close();

To insert into a table, we use a statement something like below:

$query = "INSERT INTO  user_comments(lastName, firstName, email, comments, date)"; 
$query .= " VALUES ("$lastName", \"$firstName\", \"$email\", \"$comments\", $date)";    
mysql_query($query) or die ("cannot insert the message");