To close a mysql connection we can use mysql_close() function. It can takes a optional parameter as link and closes it. If no link identifier is specified then last opened connection is closed. It is not necessary to use mysql_close() function as all connections are closed at the end of the script execution. Here is the function
mysql_close()
Note that mysql_close() will not close persistent connection created by using mysql_pconnect()
Example of MySQL connection, query execution and closing connection
The sequence is to first connect to MySQL database , then mange the database and finally close the connection.
<?Php
$servername='localhost';
// username and password to log onto db server
$dbuser='root';
$dbpassword='test';
// name of database
$dbname='sql_tutorial';
connecttodb($servername,$dbname,$dbuser,$dbpassword);
function connecttodb($servername,$dbname,$dbuser,$dbpassword)
{
global $link;
$link=mysql_connect ("$servername","$dbuser","$dbpassword");
if(!$link){die("Could not connect to MySQL");}
mysql_select_db("$dbname",$link) or die ("could not open db".mysql_error());
}
/// Connection is over ///////
/// Query details /////
$query = mysql_query("SELECT * FROM student");
$number=mysql_num_rows($query);
echo "Total records in Student table= ". $number;
///// Let us close connection //////
mysql_close($link);
?>