Use pgsql to connect to your postgreSQL database. Add
extension=pdo_pgsql.so
and
extension=pgsql.so
to the php.ini file.
This simple example shows how to connect, execute a query, print a result row and disconnect from a PostgreSQL database.
$host = "hostname";
$user = "username";
$pass = "password";
$db = "database";
// Open a PostgreSQL connection
$con = pg_connect("host=$host dbname=$db user=$user password=$pass")
or die ("Could not connect to server\n");
$query = 'SELECT * FROM table';
$results = pg_query($con, $query) or die('Query failed: ' . pg_last_error());
$row = pg_fetch_row($results);
echo $row[0] . "\n";
// Closing connection
pg_close($con);