oci_close

Closes an Oracle connection

Description

boolnull oci_close(resource $connection)

Unsets connection. The underlying database connection is closed if no other resources are using it and if it was created with oci_connect or oci_new_connect.

It is recommended to close connections that are no longer needed because this makes database resources available for other users.

Parameters

connection: An Oracle connection identifier returned by oci_connect, oci_pconnect, or oci_new_connect.

Return Values

Returns null when oci8.old_oci_close_semantics is enabled, or true otherwise.

Examples

Example #1 Closing a connection

Resources associated with a connection should be closed to ensure the underlying database connection is properly terminated and the database resources are released.

<?php

$conn = oci_connect('hr', 'welcome', 'localhost/XE');
if (!$conn) {
    $e = oci_error();
    trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}

$stid = oci_parse($conn, 'SELECT * FROM departments');
$r = oci_execute($stid);
oci_fetch_all($stid, $res);
var_dump($res);

// Free the statement identifier when closing the connection
oci_free_statement($stid);
oci_close($conn);

?>

Example #2 Database connections are not closed until all references are closed

The internal refcount of a connection identifier must be zero before the underlying connection to the database is closed.

<?php

$conn = oci_connect('hr', 'welcome', 'localhost/XE');
if (!$conn) {
    $e = oci_error();
    trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}

$stid = oci_parse($conn, 'SELECT * FROM departments');  // this increases the refcount on $conn
oci_execute($stid);
oci_fetch_all($stid, $res);
var_dump($res);

oci_close($conn);

// $conn is no longer usable in the script but the underlying database
// connection is still held open until $stid is freed.
var_dump($conn);  // prints NULL  

// While PHP sleeps, querying the Oracle V$SESSION view in a
// terminal window will show that the database user is still connected.
sleep(10);

// When $stid is freed, the database connection is physically closed
oci_free_statement($stid);  

// While PHP sleeps, querying the Oracle V$SESSION view in a
// terminal window will show that the database user has disconnected.
sleep(10);

?>

Example #3 Closing a connection opened more than once

When database credentials are reused, both connections must be closed before the underlying database connection is closed.

<?php

$conn1 = oci_connect('hr', 'welcome', 'localhost/XE');

// Using the same credentials reuses the same underlying database connection
// Any uncommitted changes done on $conn1 will be visible in $conn2
$conn2 = oci_connect('hr', 'welcome', 'localhost/XE');

// While PHP sleeps, querying the Oracle V$SESSION view in a
// terminal window will show that only one database user is connected.
sleep(10);

oci_close($conn1); // doesn't close the underlying database connection
var_dump($conn1);  // prints NULL because the variable $conn1 is no longer usable
var_dump($conn2);  // displays that $conn2 is still a valid connection resource

?>

Example #4 Connections are closed when variables go out of scope

When all variables referencing a connection go out of scope and are freed by PHP, a rollback occurs (if necessary) and the underlying connection to the database is closed.

<?php

function myfunc() {
    $conn = oci_connect('hr', 'hrpwd', 'localhost/XE');
    if (!$conn) {
        $e = oci_error();
        trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
    }

    $stid = oci_parse($conn, 'UPDATE mytab SET id = 100');
    oci_execute($stid, OCI_NO_AUTO_COMMIT);
    return "Finished";
}

$r = myfunc();
// At this point a rollback occurred and the underlying database connection was released.

print $r;  // displays the function return value "Finished"

?>

Notes

Note:
Variables that have a dependency on the connection identifier, such as statement identifiers returned by oci_parse, must also be freed before the underlying database connection is closed.

Note:
The oci_close function does not close the underlying database connections created with oci_pconnect.